1.) Player Customization: Yes, sounds good to an extent, but only as much as is needed to help differentiate from someone over the hill.
The hero customization I agree with. The city customization argument has been leveled and lost multiple times. As Josh said though: we're getting customizable defenses, so that's good enough (Well not really, but as I lost this argument months ago).
2.) Environment: No comment. Already hashed out in Border Towns thread.
3.) Forgotten Races:
a.) Dragons: Abso-fing-lutely, we Should have dragons. Their an awesome innovation to the standard Men-Elf-Slightly bad elf-orc-Dwarf SFS [Standard Fantasy Setting] Tolkein inspired game. Mind you despite Josh's optimism I think they would be harder to balance. One thing that came to mind was that Dragons aren't typically... humble. I mean if your a giant flying lizard thing the last thing you need is humility. OR, if your the Son of a giant flying lizard thing, and a human... again, no need for humility, because your 8ft tall and built like robocop. My point being, how do they have a labor class who does stuff like, build structures, mine gold, and scoop up gong (Or is that Stronghold 2). One slightly... a-moral idea that I had was Slavery. I know that sounds terrible, but who says Dragons have to be all good? Swoop down and swipe up a buncha' villagers or creeps that are lying around and instead of killing them, they work for the dragon... clan? Flock? Gaggle? Uh... Group, that is present in that area. Would be an intresting mechanic to add to gameplay.
b.) Minotaurs: Mythology of Minotaurs: They reside in Labyrinths and eat people. Their horny (Two horns, like a bull...
Yeah, bad joke, but I went there), they are furry, they are... strong? Their not very deep. I wouldn't say they would go far as a race. Now if you go Wow route, their Native American Indians. So, are we going Mississippian Indians, who are highly factionalized horticulturists (In general, before someone starts picking at me historically). Northwestern Indians, Extremely highly organized hunter Gatherers. Or Southwestern Indians, Starving... but also at times horticulturists. OR mesoamericans, preferabley aztecs: They eat people, their horny, they build labyrinths, appear in Mel Gibson Movies disguised as Mayans. Personally I don't like the idea of Minotaurs from WoW, and to go more Greek in origin... their rather unlikely to form anything civilized. I'd say they should be creeps, but nothing more. I understand innovation and heck if someone can come of with something that sound fun, original, and viable I'll eat my words.
c.) Undead: Would Be a Blast. There are multiple ways to do this. Give a different resource: Bodies, and make them do soldiers only if they have enough dead guys. If you do that, then a focus on spellcasters would be good, but you may only start out with a few. Then, sack a village and convert it's populace. Or find graveyards. If you did this, then finding magical power could be more of a sapping thing: Find another civilization, mark one of their casters, convert him to the darkside. I mean, they could really be played like the scourge of the gods that they usually are portrayed as. Further, for special units, they just need Kill another races special and raise him. Early on you can only get Skeletons which are **** easy to kill, but fast. The more you advance though, you can raise more meaty undead like Zombies, deadites, and Flesh golems (Or something). And if you get Really good, you can become, or make Lichs, demi-lichs, etc. thus artificially boosting your magic power. I mean the classic issue with undead armies is: For everyone They kill, they boost their own power. Building wise it would be sparce, maybe a small tower and a couple structures, but as time goes on and you (The caster) Grow in strength you could get more stuff. Sorry, I love the idea of undead plagues in an RTS.
d.) ...is for Dwarves. No brain-er here, we need the bearded drunken Scotsmen. Nothing more that needs to be said here.
4.) Magic: Sounds good. I mean really I don't think we'll need alot of Balance for mages, because despite their power... you'll have just a few, where as your enemy will have umpteen groups of 20 swordsmen, archers, special stuff, and cavalry riding down on the 5 mages (Just guessing)... no amount of uber spelling can kill a whole army.