It will be popular for sure. If all CS:S players switch and some percentage of CS 1.6, CoD, MW and BF players switch (which is very likely) it will easily have 100k players at any given time playing (which is like double of CS 1.6).
you put the 'Counter-Strike' title to a MOBA and it will probably make it more popular. CS:S players will switch for sure, it's not like they are loyal to their game neither they have another option to earn more or become more popular.
LoL is a big as it gets and it is already being dropped of some of the traditionally big tournaments like WCG and ESWC and probably will have to compete in IEM with DotA 2 this season. Bad games can become popular by being free or extremely simple but numbers doesn't make them good or lasting eSport titles, the same will happen with CS:GO if it gets big being a mediocre game as it is now.
LoL is still popular (with 30+ milion accounts and 1m+ players playing at any given moment). Popularity and tournaments are only slightly connected. Bad games eventually drop out. I replied to your first post where you implied that CS:GO won't be popular. My point is that it will be popular. I didn't even touch the topic of tournaments and such.