i'd say that's because the level of casting and analysis in csgo in general is extremely low compared to some other esports. the only scene that i followed that was below it was overwatch. i recall when i started watching csgo anders and semmler were the top commentators. i knew semmler. he was some guy from 2GD studio whom 2gd and incontrol would troll every once in a while. and here he is, one of the top casters of csgo. i remember thinking "jeez... the casting standards of this scene must be abysmal". don't get me wrong, anders and semmler are still probably my most favorite casting duo of csgo. the alternatives are just worse.
day9 had been doing deep analysis of pro bw and later sc2 and the dude has been the top bw player in NA for a few years.
apollo used to be great at both casting and analysis, much better than anyone in csgo scene that i can think of. tastosis are hands down the best casting duo of any scene i've ever followed both in terms of game knowledge and entertainment value.
tod and rotti used to cast wc3 before twitch was a thing. tod is a wc3 legend and understands the game on a higher level than any current csgo casters/analysts understands csgo.
dota2 had a bunch of ex pros cast / analyze such as merlini, winter, synderen etc. however, they have just as many clueless casters as csgo does who are meant to create hype and don't really understand the game on a high level.
csgo analysis used to be absolute crap until ynk, spunj, fiffy and sean got in. any one of those 4 understands the game better than thorin ever will. fiffy is the one who usually gets most in depth but like you said he's an example of going too deep to a point where it might turn off new viewers.
so yeah, that's a bunch of names of people who are absolutely superior to thorin in terms of analysis and some of them also in terms of contribution. thorin is still a superior journalists to all the aforementioned people, because none of them are journalists. they are actual analyst / casters and not the play pretend that thorin is.
in terms of relevancy, yeah i think a dude being the face or the voice of this or that esport scene is more relevant than the IT guy who sets up the equipment before a broadcast or whatever. it doesn't mean the IT guy doesn't contribute but the person hosting the show is the one people are going to remember. that's an extreme example to showcase the point.
thorin was very relevant specifically to csgo back when he was hosting and casting but he doesn't anymore, so he's not as relevant anymore imo. but even then, he was a one scene wonder and can't be compared to some of the other people i mentioned who had key roles in multiple scenes.
does that mean thorin's contribution to csgo is lesser than redeyes to dota2 for example? no, not necessarily. redeye is still more relevant when you think about esports as whole, though. at least that's what i think based on the arguments i've provided.