Is it really inconsistent with genre literature for the heroic warrior to fall victim to the wizard's magic, before then breaking free (often with the help of an ally) and slaying them? The fact is that drama *requires* failure before success in order for that success to mean anything. So called "save or suck" spells are by their nature a more distinctive and dramatic setback for a character to suffer than losing a chunk of hit points. And D&D has always required teamwork in order to overcome setbacks and achieve success.
Can you give use some examples from fiction of this happening, in combat? I can't think of any, off-hand. All the examples I can think of which are similar are either:
1) Warrior's force of will/cunning defeats the wizard in a sort of mental duel (not possible in D&D, would be cool if it was).
2) Warrior or other is not actually trapped by a spell, but is prevented from acting by fear or injury, and overcomes it - often in seeing a companion harmed (again not possible in D&D, would be cool if it was - I'd love to see a Fighter ability, for example, to auto-save on a CC spell if a companion was injured - it'd need to be auto, though, due to the maths involved).
Here's an idea: why don't we all go off and play a campaign from 1st to 20th level, ending in a battle with a grand evil wizard? Then we can come back and discuss this from the perspective of actual play experience, rather than speculating obsessively.
See you in a year.
This argument is disingenuous and facile, a remarkable combination.
Firstly, the saves aren't likely to be a big problem from 1-10 - they'll be at a fairly normal spread there. So that's not producing useful data. Hence a "1-20" campaign does not produce useful data. 11-20 is where the data will become more useful. It will be most useful in the 15-20 range.
Now, another facile argument usually follows, that being that "no-one plays those levels". Not only is this not true, of course, but if they aren't intended to be played, that should be specified in the design, and I'm quite certain the opposite is intended with 5E.
Finally, as we've already seen the results of a similar spread, in 5E, and understand the math, it's not particularly reaching to suggest we basically understand the situation.
The main complicating factor is a known known, not an unknown. That being that many of the nasty CC spells (but not the damage ones) can be broken by damage causing the caster to fail a Conc check. That's a big factor in reducing the problem, and needs to be taken into account by arguments in any direction.
So to analyze this we need to look at damage outputs from PCs and monsters at the levels where it is expected to be an issue. We also need to look at defences. If a caster can continually avoid being hit, he can avoid having his Conc broken. Neither of these factors requires a 1-20 campaign or a year of play. They do kind of require more details on the monsters we'll see from 11-20, though. So it's more like "wait for the MM". It's reasonable to assert that there is likely to be something of an issue with PC-style NPC casters, though, at this stage.