Cross-faction races
There's no real lore reason to prohibit an individual joining whatever faction it wishes, and players are of course individuals. The factions are more of a general tendency than anything else; Bosmer tend to be found in the Aldmeri Dominion but there's no reason a certain individual can't pitch in with the Ebonheart Pact or Daggerfall Covenant.
I think it's rather neat. I think I would have had more issues with it being the other way around, if you couldn't play an Argonian in the Aldmeri Dominion.
Classes
What class you pick decides one thing: Your class skill lines. That is a rather small fraction of the skill lines available to your character - you still pick freely from six weapon skill lines, three armour, three (for now) guild lines, world skills, crafting skills, and PvP skills.
Even with classes, there's still
5.09 E58 combinations available, so I really don't see classes as being more limiting than e.g. the racial skill lines (known as racial bonuses in previous TES titles).
Stamina and Magicka
I don't feel the system is limiting at all, and I don't see what "correctly implemented" enchantments (whatever that entails) would add? You can already use enchantments to improve e.g. max Magicka, which then improves your magical abilities proportionally. You can also add e.g. physical damage via enchantments, or magical, or... rather a lot of things.
Necromancy
It will come. For now, use Nightblade Siphoning skills and "drain" enchantments on your weapons, work on your diabolical laugh, and kill every rabbit or pony Guar you see
