what you consider as a "fuck up" was intended.
look at the pool of viable mid and top laners, and even junglers compared to bot lane.
bot lane is currently the only lane in the game that is monopolized by a single class of champions. riot wants to get bruisers and mages as viable alternatives to marksmen in the position of duo lane carries.
thats not to say, that marksmen arent supposed to be playable anymore, but you will have to get used to a lot of new matchups, of which some of them will be hard to deal with, depending on the champion youre playing.
for example if im picking garen on top lane, i will have to live with the fact that my opponent might pick teemo, quinn or heimerdinger and make the lane incredibly hard for me.
you will have to live with the fact that some of those non marksmen are countering your champion in lane, and adjust your playstile just like we have to do on mid and top lane.
another problem is, that marksmen being mandatory fucks with the viability of other carry types. picking a juggernaut on top lane and a marksman on bot lane immediately messes with your teamcomp. its easier for a team of 4 men to support one ranged carry, than for 3 to support one ranged and one melee carry.
if you can play a juggernaut like darius or morde on bot lane, you still have the option to form a teamcomp around them with the other 4 picks, which makes it generally more viable to pick these champions as carries.
and can shit on the entire team, or a skirmisher getting 
can 1v3, or a fighter with 
can 1v5.
