So, a about half a year ago my first Morrowind save got corrupted somehow (I was overwriting saves, I stopped doing it eventually and then the save just died). I can't be bothered to go through all the palaver of installing Wrye Mash, with all of its Python nonsense, if the savegame fixer is not a guaranteed solution. I didn't get very far with the character, though, so not too many spoilers, please.

As a result I'm looking at starting again, but not with a melee-oriented character like last time. The die-roll combat for melee and archery was really frustrating anyway. I'm thinking of trying a mage, with a particular focus on House Telvanni, for RP and quests (Tel Uvirith ftw). With this in mind, do I need to avoid the Mages' Guild?

I'm also looking for advice on the magic system itself (as a player who is used to Skyrim and Oblivion), what are absolute must-haves for a destruction/conjuration-oriented mage, and also mods I can use that are compatible with MGSO. I'm going to use a mod that gives magicka regen, as lugging around a large amount of restore magicka potions seems like a really rubbish idea to me. Unless you guys have got better ideas?

And then there's the skill/attribute system. I'm not really a min-maxer, but I was also wondering about optimum setups with regards to levelling speed balanced with skill advancement.

Why not use http://www.gamesas.com/topic/1106095-wrye-mash-stand-alone/? Which requires no messing with python files.

Very simple to install, and if you're going to use mods you do need Wrye. It can fix almost any problem.
Chances are very good your old corrupt save was fixable. It's rare we can't fix a save file from even the most insane problems

MSGO is 99% replacers, which can't conflict with other mods if they tried They just overwrite in order of installation.

Which means basically all mods are compatible with MSGO, unless you use a mod that does the identical thing that one of the MSGO mods does, but why would you install one of those?

You could join both Telvanni and Mages Guild, but there will be some conflict near the end of the Mages Guild. But you can choose to not do that quest, although you'll never finish the Mages Guild. From a rp perspective, you might want to pick one, as they do hate each other.

The dice roll combat is mostly just annoying at the start, when your skills are low. Keep your fatigue full at all time, and you will succeed much more often.

(I personally think it's the best combat in any TES game, as it's based on your character's skill, not your skill to mash buttons fast)

Using a magicka regen mod is a good idea. I recommend http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=7853. It's lightweight and compatible with everything. (as far as I know)

Level your skills naturally, and don't obsess over getting the 5 multipliers. The game really takes care of you, unless you're using skills that have nothing to do with the skill you picked as your Major/Minors.

http://morrowind.inventivegamer.com/tools/chargen/ is a great character planner tool, essential. You can show us your planned build and ask for feedback on it.

And here's a link to remind you of the http://www.uesp.net/wiki/Differences_Between_Morrowind,_Oblivion,_and_Skyrim