Not sure what you mean by fun being diminished because you don't want to use those guns. You can always use them. But anytime new content releases, it doesn't matter if it's RNG or not. Something might release that you find to be better.

But if everything getting released is RNG, the fun is severely diminished if you need stuff that isn't RNG. You're limited to previous items. And not actually utilizing the new stuff even if you paid for them. Not to mention, previous items being removed from the game altogether. It's like what can be done? Why even play. Stuff is getting removed for no reason. And the stuff being added in is overboard with RNG.

Having some choices is always good. There have been choices in rewards. Like you choose which sparrow you want from a list of three. Either way, as long as you're not stuck with some randomized version of an item, it's fine.