diamond generators aren't the only generators. Iron generators will work faster too so those whole 3 minutes will be a lot shorter. The time to build towards mid doesn't change, so in perspective it makes it harder to pull off.
Although that's
probably true, it doesn't change the fact that you're able to get a punch bow much quicker than usual on any map. Faster gens = faster gens = less waiting time after you pick up the max cap = faster punch bow, which all means it takes way less time than usual to set up shop to start mid camping.
Heck, you'd be able to equip everyone with punch bows much quicker, and with iron armour too. You'd be able to control mid and make your base an impenetrable fortress in the course of 5 minutes. Casual players wouldn't stand a chance.
Aight, the no projectile talk is going completely off topic, but:
If that was the case people wouldn't vote for it.
The problem doesn't lie in it being a bad mode, but rather the fact that it's a votable option. Quite a lot of people like it, and almost everyone votes for it. You're pretty much bound to get into a game with a rank almost every game of solo SW you play, and all of them vote no projectiles. What's worse, is that with a tie between normal proj and no proj, it picks no proj anyways.
If you don't like no projectiles, you're screwed and pretty much forced to play it whether you like it or not. This makes skywars unplayable.
No Projectiles was a good option. You can just build bridges without derps constantly shooting so you have to build a bridge with a wall..
Honestly, the best thing I can say against this is: git gud.
I'm not asking them to remove no projectiles, but rather to make it a separate board. It's simply impossible to play normal projectiles.