I can understand why some might be frustrated with the whole "start as a thinblood" thing. I'm not bothered, personally. I like the idea of progressing your powers and then later choosing a clan whose actions/beliefs (or just cool powers) align with what you want.
Progressing your power is fine and good, but from rulebooks thin-bloods are limited, you cannot learn disciplines the normal way you need to drink potion to have one ability temporarily, if i progressing my power i don't want to be limited to one temporarily ability.
Also, to join clan later just to get one ability from them that is probably also temporarily, why join Malkevian for example if your character is not one and don't get all the pro and con of that clan, best part of VtmB was clans and how your character was different, Malkevian way of talk was best the voices you can hear all add to that unique feel.
I see meany people on steam or VtmB reddit attack people who are not pleas with thin-blood MC,this is rpg, and developers say you are not full vampire but you make your way to the top, why you want that all is given to you on a plate, no one want anything on a plate, in first VtmB you start as vampire but you are weak you level up you progress your power and make your way to the top just in any RPG, but this sound like if some developers come and say we make warhammer 40k game, where you start as low imperial guard and you rise to the top and you end up like space marine, that is not how thing works.