Kind of on topic, last night I played about twenty games on Megamek vs the bot (I know, I know) where I took a stock Crusader 3R up against a variety of solid medium mechs. Griffins, Wolverines, Hunchbacks, Vindicators, Centurions, etc. I played at least two to three games against each medium to give a good sample size. In every single case, the Crusader beat the ever living tar out of the mediums. It wasn't even close.
Now, generally I had a BV advantage. And I had a weight advantage. Most of the mediums would have a BV of between 1000 to 1100, while the Crusader was about 1300. 4/5 pilots for everybody. Two random mapsheets. Just a bunch of one-on-one matchups where I start at one side and they start at the other.
What I learned was... quit taking the Crusader up against Thunderbolts and Marauders (I played a few of those too, and they didn't go nearly as well). But if you consider that medium mechs are supposed to be the "average" in 3025, then the Crusader is really powerful, and really survivable. The ammo bomb never came up, because my short ranged firepower was better than theirs, and my armor was better than theirs. Normally they'd be destroyed and I'd just have armor damage (maybe a stripped leg if they got in a kick).
I could definitely see a Crusader lasting a very long time during the 3rd Succession War. You would want to avoid the best heavies one on one, but who wouldn't? If you think of it as a fairly badass overweight medium trooper that can also provide Catapult-level long range/indirect fire, it works great. A Crusader pilot would need a degree of situational awareness -- keep track of where the things that can kill you are -- but really every mech pilot does. If you find yourself in short range combat with a dangerous opponent (or with damaged side torsos) and you've still got LRM ammo left, you did something wrong.