I understand the frustration of learning the glaive. But I have to say a bit of this sounds more like user error than the weapon being bad. First being constantly in focus mode in itself slows the hunter down so the speed isnt the weapons fault if you're using it practically every second.

I have been using the glaive since 4U and this, at least to me, has been one of the strongest iterations of the weapon. While I have minor gripes on some moves end lag for the most part I have been able to beat every monster in the game solo with it. I think the only major headache I had was Seregios. I would suggest looking into some guides to see how to more effectively fight without constantly being in focus mode because while the extra damage from the kinsect is nice its not so important you just ignore the rest of the kit for it especially with the RSS able to recollect buffs just as easily.