Can you still make a BRETON ATRONARCH ASSASSIN-style character and be the universal soldier, alright at everything - decent punch, godly protection from magic attacks, stealthy and with thieving utility skills, and enough mana supply to be able to dabble in magic when needed, as needed? Is there still alchemy to make this build viable, since it can't recover mana and default storekeeper potions in all Bethesda games suck?
Or did they make builds more specific and restrictive, forcing you into class-style constraints and making you choose between punch, magic, and stealth?
If by punch, you mean melee, then yes - my character is an imperial spellsword assassin, with points distributed fairly evenly into all 3 'builds', and it works fine. Not amazing at most things, but decent at all, and very versatile.
Uh, actually not.... Breton race + Atronarch birthsign (at least in the previous games) added 50% magic resistance + 50% magic absorption [attack spells cast at you fizzle + get added to your mana] + a lot of mana [don't remember how much, but very significant] .... at the expense of not being able to regen mana over time or during sleep.
In effect, gave you the ability to
a) have a mage dependent on leeching from offensive spells cast at him for mana regeneration
b) be a fighter, thief, or fighter/thief with great magic defense (50% fizzles 50% over that absorbed as bonus mana = only 25% make it through before any other resistances later gained) and extreme ability for untrained magics due to high amount of mana.... that's difficult to restore outside of magical combat {easy enough to fix w/ alchemy skill, all too easy to fix when regularly absorbing magical attacks, such as from hi-level enemies)
c) go through every single quest in prior games, without having to level far past the expected level for the quest - because such a char has sufficient mage/thief utility skills to deal with most barriers between you & quest goals; enough fighting skills to punch your way through to the objective; several times the HP you'd need to defend against magical attacks, of which less than 25% ever make it through (since 50% of magical damage is blocked + 50% on top of that is absorbed + that's before any items equipped and spells cast); enough mana to cast utility crap like open spells at high levels without practice {since you have 5-7 times the mana an average fighter might have}
d) be safe from any magic-user in the game - since magic attacks more often feed your mana than damage your health, you can just keep a healing spell on hand, and defeat any magic-attacking foe, no matter how strong, no matter how weak your attack is (assuming it doesn't kill you in any 2 hits)