Orkhepaj: GoG should work more on newer games up to datedness and mod support :P
Best would be if DLC-s would be cross-platform able.
IMO one of the most important aspects of DLC is possibility to play with people who don't own it (which of course occurs in case of games with MP mode). But this thing is mostly depending on devs. Fortunately, developers of Gladius made it in optimal way - whenever there is DLC, there is also update for base game which basically contains new stuff (DLC itself is just small package which "unlocks" content). In multiplayer you can freely play with anybody, even if you don't own any DLC at all. And while you can't play as one of the additional races if you don't own DLC, you can still have additional units from reinforcement pack (in multiplayer), even if only host owns the DLC.
Sadly, I must agree that no access to mods is an issue for some games on GOG. Fortunately, in case of Hotline Miami 2 one of the users made great work to gather content of additional levels/campaigns from Steam workshop and packed them to make available for GOG users, but I guess that it's not always possible (not to mention that it requires from someon to won game on steam and make all stuff connected with downloading mods/levels/etc.
Anyway - getting back to topic - I've just played a bit in Tau DLC and for now it seems that on the one hand Tau have relatively similar model of economy as IG (for sure the same resources), they have great advantage with auxilary units (ability they can use once on every turn - for some amount of influence they're taking control over neutral Kroot Hounds or Vespids (new neutral unit) squad. It seems to give them very noticeable advantage at the beginning of the game.
