Obviously the game has a multitude of problems currently but I think unit flavor is a huge one. The warnings signs for me is that Stardock seem intent on running everything off raw stats and numbers. Weapon does X damage, next weapon does X+2, etc. The worrying thing for me is that they seem to like these sorts of system whereas I find them very 1990ish.
In 2010 strategy games have moved on and almost all decent strategy games being released in the last 5-10 years have their unit-flavor driven by special abilities. Can a unit system designed around special abilities and unit flavor as much as raw stats make that much difference ? - Hell Yeah.
This probably sounds kinda condescending but sometimes I wonder how much games like AOW: Shadow Magic, MoM, Heroes 3/5 and Kings Bounty (new ones) the devs have played, and would encourage any team members that haven't invested time in these games to go back and have a serious play. Obviously those games are quite different to elemental and I respect that (I'm not asking for clones of these games in ANY way), but each provides interesting and far superior examples of how to implement a flavor-some unit system than what Elemental provides. In fact many of them are light years ahead.
Take the new Kings bounty games for example - I love the tactical combat in them but its because of all the great passive and active special abilities that make units truly unique. On average each unit would have 1-3 passives and 1-3 actives in that game. If you took away all the special abilities in that game and just left the raw numbers, it would go (IMHO, at least the tactical side of it) from a 9.5/10 to about a 2/10.
The spells are another area of serious concern in elemental where lack of flavor and strategic importance is readily evident. I won't go into this as its been shouted from the rooftops by many, many people already.
I just really hope that Stardock can also see how bland and boring a lot of these systems currently are - because if they can't I fear Elemental's only success will be in its ability to allow modders who do understand these things to turn it into something more interesting.