Zardnaar
Legend
One of the biggest issues for casters is that at higher levels,saving throws improve on the side of the target, in general, there was nothing on the spellcaster's side that really improved the odds that their spells would succeed (at least not in core, I think some options came out that compared their level to the opponents and applied a bonus or penalty). In 3e onwards, spellcaster's had a greater chance of their spell succeeding because their spell save DC/attack bonus increases as they level and often there were additional bonuses that could be applied to improve their chances. As far as I can recall in 2e, only specialists penalised their opponents saving throws (by only 1 point) and there were some individual spells that made the target save at a penalty, but otherwise, your spells that targeted opponents could end up being quite useless. Better to buff your allies or focus on spells that don't require a save.
I played an enchanter once and focused heavily in spells with that save penalty built in. I think conceptually 2E MR as a flat number and TSR era save scaling is a good idea.