I'd say the differences between races is more apparent than in most 4X games, but on the other hand, doesn't compare to most RTS games. Which is fine, because Sins is supposed to straddle the two genres.
I personally think this is the balanced position.
Those arguing that Sins has as much race diversity as a standard RTS are just throwing out a knee jerk defense. Starcraft, Warcraft, Dawn of War, and even the new Earth Assualt show a ton more diversity racially, down to economic models for each race.
Sins has less racial diversity than most RTS'es. BUT it doesn't NEED or BENEFIT from having as much diversity.
Diversity comes from your choices DURING play with whatever race you choose, because the options are so much more wide-open than a RTS. That's the way 4X's tend to be. For example, racial diversity in MOO boiled down to a couple of racial bonus traits. But this affected the way you made all your other choices (choices open to all races, by the way).
So, objectively I think you have to admit it has less diversity especially in terms of units and structures. However, that's about all the diversity that can be incorporated without making the game extremely unbalanced or complex.
While indeed a bit of a knee jerk defense, most of it isn't that far off if you think it through. In DoW, only 1 race does not use the exact economic model as the rest (Necron). The other races have barracks, mech buildings, turrets, research buildings, power plants, req "extractors" (for a lack of a better word) and so forth, so by a glance, everything is exactly the same structurally with buildings, with the same number of upgrades in their HQs for the most part.. There are slight variety but it took them to make a total of 7 races and 2 expansions before all that came to be.
The real variety on DoW does not come with each race as all the buildings are placed exactly the same in the building menu for each race (which was a complaint about Sins in this topic) as well as with many races, the units are placed same-ish too, according to them being long/short range. The variety in DoW truly comes with how each race is meant to be played and by what techs you wish to pursue, which is the point people are trying to make about Sins.
In Sins, you have to use your capship abilities correctly and at the right time for them to have the desired effect. And you need to activate them manually as well, if you want the greatest effect. I'm far from the greatest Sins player in existance but even I can see the folly of the computer deciding to make my Vasari ship immune to jump inhibition as soon as it faces an enemy ship, instead of when I make it leave the well, as well as having to use the push ability on 1 fighter group instead of the following 10 with Advent.
While I do think it could do well with a few special ship types for each faction, it's also worth noting that since this
is a 4x game too, it means certain things must be similar as well. If you have ever levelled a capship to 10, you'd notice that if, say a Vasari battleship, started with even just a little more advantage than it has now, it will by the last tier be so much better at ship to ship combat, the rest of the capitals can just pack up and leave if you bring a few of them and a couple of support ships. One of it's abilities at level 3 is a 75% faster cooldown and 250% faster shield repair, I believe, and add to that the enlarged antimatter cap techs, faster antimatter regen, shield/hull regen and weapon bonii, you should begin to see why there is a need for them to be fairly similar between all races.
