Much of the original games' cut content was re-added in the mod, as well as in general, more toys for most factions to play as - the objective being that the player is generally given more choices as to the composition of their armies.
DoWpro also implements new content from certain other mods (used with permission).
Space Marines are rebalanced around being an Elite unit army, with their Tactical Space Marines taking 3 population.
Chaos forces play similarly to the Space Marines, but with a greater focus on melee combat and daemonic support units. Their vehicle choices are more limited than the Space Marines, but versatility in units like the Defiler allow one unit to cover many roles.
Orks are rebalanced around being a melee Horde army (like in vanilla), except that they have more varied armor types and ways to deal with hard counters (which Orks lacked in vanilla, noticeably against the Eldar Warp Spiders).
Eldar, being more like Vanilla, are no longer about massing Dark Reapers (which is the most prominent opening in later expansions, depending on patch).
The Imperial Guard are rebalanced towards being a Horde army, where a guardsmen squad costs 100 requisition (from 160). In order to defeat Elite unit massed gunlines, the Imperial Guard rely on a combination of disruption, dense formations, siege warfare, and fighting in multiple places at once by utilising their numerical advantage. Expect atrociously high casualty rates even in victory.
Tau emphasize mobile firepower that is rebalanced more towards the use of infiltration, jetpacks, ambushes and diverse unit combinations. Additionally, Stealth suits begin as hunter-killer units, instead of Tier 0 capper units (with Pathfinder units taking their place).
Some factions are changed more than others; Necrons use a unique mechanic where they need to expand their area of control and actually gain resources in an effort to actually force them to take and hold territory and play more like the rest of the factions, as opposed to how they originally played.
The mod implements a number of cosmetic and minor improvements, in an effort to help keep some of the units closer to fluff. As an example, the World Eaters-exclusive Khorne Berserker in Vanilla is replaced with a Black Legion-style Berserker that includes team colors to make it look like a Khornate unit that happens to be in the warband.
Significant changes to the factions' tech trees (and subsequent necessary rebalancing), such as Grey Knights and Khorne Berserkers being available in Tier 1.
A series of "pancake-style" tech-upgrades ala 90's strategy-games, e.g. StarCraft.
Tweaks have been made that reduce pathing issues, such as reducing model sizes of both infantry and tanks as well as the removal of clipping (similar to Starcraft).
Large scale army control in 1v1s is more common, because players tend to have more squads to control.
Removal of the Fire on the Move Accuracy Penalty implemented in Dark Crusade, thus the original game's 'run and shoot' unit control is emphasized.
Capture rates were reduced making it faster to take and re-take the map. There is more leeway to be less predictable in your capture order.
Critical Locations provide twice the Requisition.
Jump units (such as Raptors) capture points at a faster rate.
Issues and Criticisms
DoWpro's focus on Tier 1 battles with significant attention paid to expanding and holding territory as opposed to the fast-tech-and-fight gameplay of Dark Crusade and Soulstorm is not for everyone. It also has a number of gameplay issues and bugs all its own.
The mod removes Flyers.
It also fundamentally changes how the factions added in the expansions play, and not always for the better. Those who are fans of how existing factions or mechanics already work or feel (e.g. the uniqueness of the Necrons, which the mod outright removes, or Dark Crusade infiltration) will not enjoy it.
Balance has focused primarily on 1v1s, as opposed to team games.
Games less frequently reach Tier 3 or Tier 3.5 (which is a Tier level that some players may prefer).
Units feel much more fragile than they are in the originals, because the Fire on the Move changes allow for more concentrated firepower as multiple units gang up on a single unit.
This ironically makes for a game that while certainly much more varied than Vanilla, also tends to culminate in much more protracted battles over the course of a given match, and can quickly boil down to drawn-out battles of attrition dictated by "who makes the first major mistake". Matches can also be decided in the first five minutes - and still last for over thirty. In certain match-ups, such as Orks vs Imperial Guard, this is very noticeable.
If there is a specific Build Order that you wish to play (which worked in DC/SS), there is a decent chance that it is no longer viable in DoWpro. For example, 3x Dark Reaper is not as viable, as they are now hard counter units. Also, it is much harder to aggressively place turrets as they require a Control Zone to be built in.
The mod encourages mid game transports (as they can be built from the HQ at Tier 2). However, transport gameplay is not as smooth as Starcraft.
Chaos is now more similar to the Space Marines (like in Vanilla), whereas in WA/DC/SS Chaos is significantly different and more unique.
The complex counter system means that there is a steep learning curve from the original. For example, Flamer weapons are highly effective against Demons.
Optimizing your units requires that you understand what armor types every unit has in the game, and roughly how well every unit's DPS performs against those armor types. Incorrectly targeting the wrong enemy unit is often excessively punishing, and encourages players to analyse Damage Per Second spreadsheets.
Even some units which keep fundamentally the same role they had in the original game may be changed in implementation, to the point where their use is fundamentally different in practice.
Jump pack units are less mobile in DoWpro. For example, in the base game at full charge the Assault Marine Squad will have 2 4/9 jumps available, requiring 110 s total to recharge from empty. In DoWPro, it is 1 4/9, approximately. From full charge if you jump, there is a 20 second timing window as you wait for your next charge.
Progressing through the Tech Tree as Eldar can be confusing if you're unfamiliar with the vanilla game.
If you were a fan of the Eldar Ranger squad (as in DC/SS), then you may be unhappy because it requires upgrades to achieve the same ranged harassment potential.
Tau is now a mobile shooty army instead of a stand-and-shoot army, which may or may not be in your favor depending on how you like your Firewarriors. On the other hand, you can now pick both Kauyon and Mont'ka within a single game.
The Imperial Guard have two pieces of Wargear called Ordo Xenos and Ordo Malleus that upgrades the Inquisitor, but where is Ordo Hereticus?
Certain build orders, such as opening with ASM or Raptors, are now more difficult to perform.
Artillery units such as Basilisks and Whirlwinds no longer do tons of damage to all infantry, which is what you may expect from artillery. Instead, they are used primarily for disruption, morale damage, and building siege damage.
Certain combos from DC/SS no longer exist in the same way, for example Grey Knight's Psychic Inquisition combined with the Librarian's Smite for impressive Area of Effect damage.
Further, it has a number of unique bugs (some of which might be blamed on the core game-engine), some of which are only avoidable by being aware of them (i.e. have to actively be played around by the player). Core gameplay changes, such as Fire on the Move no longer reducing accuracy as significantly, exacerbate pathing issues on some maps, which hurts Horde armies more than Elite armies.
- http://www.moddb.com/mods/dowpro - Mod DB page.