i think teachables should be unlocked at lvl 30-35-40

Although the grind for those who play multiple characters has been reduced it is equally true that the grind for those who play a single character has increased dramatically. Before the update to unlock the teachables you had to spend around 800k bps to reach level 40 and you were alright, you just had to spend a small difference to get them T3 on your main. Now to get the teachables you have to spend around 1.6m bloodpoints to bring to P1 the character who owns the teachables you need + an additional 200k or 300k bps to bring them T3 to your main character, these numbers come assuming your main character is around level 40 but even ignoring it we can see that for the average player the grind has actually increased.

My suggestion is to bring the teachables back to levels 30-35-40 more easily accessible by all players (so you will have to find the T1s in the bloodweb of the other characters as in the old update) and keep the functionality of the perks already unlocked in everyone's inventories if the character who owns the teachables concerned is P1, P2 or P3 (obviously as now, depending on the prestige, the tier of perks in the inventories will be different)