What are your opinions about games that have no spellcasting PCs?

Personally, I love them. Dealing with dungeons or other content which a lot of the problems could be overcome with the right spell, but without anyone who casts magic takes on a whole new feeling for me; it feels more heroic. My last party had a fighter, a monk/ranger, a monk/barbarian and ... okay a cleric. But the cleric wasn't very effective and didn't really have a good grasp of his library of spells. Mostly they were used to deal damage and heal. It was an adventurer's league game, so occassionally had a wizard or sorcerer drop in. However, whenever that happened, the game became a lot less interesting because the wizard almost single handedly won combats or completely removed puzzles as challenges.

When playing without a spellcaster (or at least, for want of a kinder term, a competent spellcaster), you have to really use your wits to solve these problems which are way bigger than yourself. It starts feeling like playing in a world like old Germanic myths, with like Sigfried or Beowulf, where a dumb character is a dead character and you really have to think about everything in your arsenal to defeat encounters you weren't meant to defeat. Like there was a time where a certain module was run, my character, a somewhat prissy noble (who I have talked about a considerable amount here) was confronted by a hallway that heats metal. If you know what this is, great, if you don't, don't worry. I'm trying not to spoil any content. The monk in that adventure just walked through, the ranger too. I think they contrived some way of pulling their money along. Minimal problems. The rest of the party had a way through the dungeon except for me. The fighter, decked out in metal... not so much. Anyhow, they got tired of waiting for me to develop some sort of solution and it became important that I hurry up. So this character threw herself down into the dirty water, soaking herself through then got up and, uncharacteristically, yelled as she charged headlong down this cooridor. The dm rewarded my creativity, allowing me to have fire resistance for the first couple rolls.

I think limited power and restrictions make for more interesting gameplay choices. They force the players to react to problems more interestingly. Or they allow certain characters in combat to do interesting things. Like flying  or needing magic weapons. There was another encounter where my brother's character, couldn't hurt the golem. My character was using a +1 rapier, borrowed from a bard, because they basically had it for decoration.  This was another adventurer's league game, so we had a few other characters. Some of the characters who couldn't hurt the golem ran and cowardly hid outside the door. I guess they were waiting for us with the magical items to die, so they could take them from our corpses? My brother's character used the aid action to make the golem easier to hit by the players who could do damage. He used the restrictions to come up with some interesting choices that we still talk about from time to time. Had that restriction not been in place, we'd probably never talk about that adventure again.

That's my take on it, what's yours?

I can see how in AL, playing a caster would grant greater tactical flexibility, as the adventures are designed accessible to a very wide audience.

I play in home games with friends, so I can pick monsters that will challenge casters too (like fiends with limited magic immunity)