Teammates who don't peel = big problem

Glass cannon build = viable assuming you don't get focused too hard

Usually will be some enemies chasing you. If positioned well you should have a lot of your teammates in front of you so that if someone like a tanky dps dives at you someone with CC can peel for you (Support Alistar is a great example of this!).

You still do all 100% of your damage while being glass cannon.

In solo queue noone peels so tanky dps are pubstompers. Also this does not mean tanky dps can't be overpowered- for example look at pre-nerf Irelia who was virtually resistant to CC.