Hello OP
To answer the question ''why is there no accuracy buff?'' we first have to take a look at areas of the game we cant have buffs besides gear stats.
Accuracy:
Great Hall
Aura
Masteries
The same goes for resist. Now before we explain why there is no acc/res buff, let's take a look at the dynamic between critical rate % and critical damage %
Critical Rate
Buff
aura
masteries
base stat
critical damage %
great hall
masteries
base stat
Out of this observation we can subtract the following question ''why is there no critical damage buff?''
could it be because:
there is a critical damage buff in the great hall?
there is a total of 30% (potential) extra cdmg% from masteries?
there's already a potential 55% cdmg +50% base (on average)
or 35% (without flawless execution) +50% base (on average)
The reason I brought up the c.rate% c.dmg% example is to show that from where they come from, it is already at a balanced point, any different and it would tip the balance of the game, and same can be applied for the accuracy
accuracy
greathall 80
aura (u could get 50 on average, some higher/lower)
banner 70-ish 5* (96 at 6*)
benefit of having no accuracy buff?
you get to focus on other important buffs,
you get to have those ''global stats'' affect everyone
you can get acc at a higher value from gear stats/ banner main/ amulet sub/
TL;DR Balance of the game compared to where you can already get accuracy beside a buff
Regards
Ophe