Yes, the cannon is not great. It, however, does NOT struggle in killing BR2 vehicles. It absolutely does NOT fail against the Pz3N. I’ve killed many of them. Conversely, when I am in a PZIVE, which I used a lot until I got the PZ3N, I had no difficulty taking out Crusaders, and woe betide them if I caught them from the side. That 14MM armor is an absolute joke. I’ve had games where I lost the treads on my AC1 and continued to use it as a practically indestructible machine gun nest, right outside an enemy strategic point. Plus, it has 5 crews to the Crusader’s 3, which allows for a bit more longevity.
Trying to figure out how to 1 man a Crusader (which I’ve done) is not exactly easy for a new player.
When I play Crusaders, I make sure that I’m constantly moving, and keeping an eye out for other tanks and AT guns b/c one shot and you’re done.
The only time I experienced those type of quick kills from enemy tanks while in the A.C. 1 is if BR3 Germans were playing, or the occasional lucky shot from the higher end German tanks.
Telling a newcomer to get into a Crusader instead of a more heavily armored tank (like the Grant) makes it sound like you want them to die quickly. They’d be better off in the Daimler MK 2 - at least they’d have the benefit of speed, and wouldn’t be fooled into thinking they actually had any armor protecting them.
For comparison sake, here’s the armor in the vehicles mentioned. And notice the turret armor on the AC1.
Spoiler
The Crusader should really only be considered once someone has gotten “pretty good” at tank fighting. Otherwise, they will just get frustrated as they get oneshotted repeatedly by opposing tanks or even worse by explosives that even without a direct hit, will blow up a Crusader from several feet away.