I want advice on making better coasters, because I feel like all the coasters I have made (not all of them i have uploaded) are the same thing, just tweaked a little.
Also, is it ok if a coaster is too slow, to make it a powered launch?

The Question is, do you want to build "fun" or "realistic" coasters?

Fun Coasters can have all whatever you want to have on them, so if you want for an example an "power-launch" on an "B&M Inverter" well, than make this .

If you want to build "realistic" looking coasters its helpful to look around and download some of these and take a look about it. So you can see which things are importent and what do you need to build.
Additional to downloading "real" looking coasters could be to take looks on some pictures about real coasters, exspially the type of that you want to build -> Intamin, Arrow, B&M, GCI

And now it comes the horribly and most hated sentence: it's all about practice! sounds bad, but it's the truth! Every designer starts up with not really good looking things, but after building hundrets of coasters/parks you getting better and better

Soo long, Cobra