Re "Teleport negatively affects bot lane"
I don't think this is a legitimate concern.
First of all, you can see opponents lay wards. Second of all, you can see the teleport channel if you ward yourself. TP rewards vision. If you really want to get a handle on teleport, put some strengths into its counterplays. Extend trinket ward duration by 30 seconds. I just pushed the hell out of the lane with ADC so we go from our tower to theirs in 20 seconds? I should anticipate that they put a ward in our bush. Or the jungle bush.
So, let's say Leona all ins and stuns one of us for the TP gank to be on time. Doesn't that mean we pushed the lane too far? Why would I push all the way up with their support and ADC having any kind of health left and no vision?
A main point I'm making here is please don't reduce any motivation for players to put wards on the map. More than anything else, it really is a vision meta, and there is not much motivation in normal or low ranked for players to see more than 5-10% of the map not occupied by minions.
Yes, there is split pushing that is a concern and I might imagine that this is actually one of the major problems that you see outside of bot lane. Tryndamere teleports when minions are up past outer tower and takes inner tower and an inhibitor tower before anyone has time to even get there. I know, I do it a lot and it is kinda cheesy. Honestly.. I think split pushing in general could be curbed a little bit, maybe have towers give random debuffs to one champion? Mainly attack speed and damage - or I could see reducing defenses as well so one person could legitimately deal with them quicker, before the tower falls. Give towers more power - like I said, buff the things around teleport that help to counterplay it. As it is it adds a great dimension to the game and is a lot more fun! It is more time spent in team fights and taking big monsters (and towers.. hehe), and less time running up an empty lane. I don't see that as a bad thing, even if this 'useless time' offers some sort of counterplay - I don't think it's counterplay that's worth having.
shrooms. Aha who needs wards?