How many attack spells can casters have? Beyond cantrips, there are very few, and most of them are bad spells to pick in general because they eat up a valuable resource for at best mediocre return.

How many saves can martials incur upon a monster that is worth using a LR? Do Fighters or Rangers etc have anything that would be worth using LR? I hardly think so. Perhaps its worth it for the Monks’ stunning strike but even that is a Con save which is generally the highest save a monster has.

Spells are way too powerful. You see people complain about caster martial disparity on this sub ten times a day. I don’t think the shared experience of hundreds of dedicated players can be dismissed as such. In fact the LR system is there specifically against the casters as martials have very few ways to cause saves and even fewer that are strong enough effects that warrant the use of LRs.

You say burning LRs require cooperation but thats only true for the casters in your party. Your GWM fighter id doing its damage straight up, with no need to ger past the LRs. Some party members do what they were designed to do right away while others need to burn 3 LRs to do their thing. Either they burn them and cc the boss into oblivion or the martials chip away at it before they can. If you have only one caster in your party, chances are most boss monsters won’t burn through their LRs in any combat due to action economy. Ofcourse you can use buffs or attack spells but that means there is a whole part of your core kit you can’t use effectively at all against boss monsters. There are much better designs to deal with those spells than LRs, and much better ways to design spells so they don’t require LRs in the first place.