It comes down to reason. Riot can't do everything, and the more queues they have up the longer it takes to find games, the more it costs them, and the harder it is to fix issues. That is why they don't have every gamemode always up. It isn't that it isn't possible, because they can afford to do it, but queues would stagnate, the already long queue times would skyrocket, due to queue times skyrocketing people would grow bored and leave. As people left queue times would rise even more, resulting in more of the same.
I watched the same thing happen in Tribes Ascend, a really fun and unique game, that had so many queues as well as the ability to host your own games that Queue times went from roughly 1-2 minutes to half an hour plus if you were lucky.
A game like LoL just can't feasibly exist if it can't keep queue times down, and if it comes down to making a small minority sad, in order to benefit the vast majority, then choices have to be made. In an ideal world they would keep both queues up, but the fact is that this isn't an ideal world. Choices aren't always easy, and rarely lack consequences. Decision making is about choosing the path that does the most good, and the least bad, not the one that does no bad, because that path just doesn't exist.
If removing Draft pick would sadden 1/10th of a player base in EUNE and cause some of them to leave, but it would make half of the player base happier and keep them in the game, then it comes down to choosing the decision that hurts 1/10th of the player base, or half the player base. Sometimes not doing anything can be worse than making changes, even if the decisions are hard ones.
NA is different due to the number of people that play Draft, unlike most other regions. Removing it here would hurt a very large chunk of the player base, and as such the good it would do might not outscale the bad.
I think it just comes down to Riot isn't saying "No man, no problem." They are saying "We will do what is best for the many, not what is best for the few."
Keep in mind that next season is introducing even more queues, which will slow down times. I am guessing these changes are preemptive preparation for that.
