So i decided to offer some various ideas to fix credo questing.
Listed mechanics that can help to fix credo questing (IMO):
1. 1 quest per next level
If your first credo will require 2 quests per level, and next credos will add +1 quest - it will be easier to make multiple credos you need. With this decision it will be a bit easy to make a lot of credos, so i think credos must be limited by other things that listed below.
2. LP and EXP requirements for credo
If credo questing will be easier - it will require other limitations. Simply increase requirements for starting credo. Each one will require significant more exp and lp than before.
3. Minimum stats to start credo
A minimum of stats required to start a credo. The more credos you have - the more stats will be required to start credo.
For example if forager will be your first credo - it will require 30 exploration and 30 perception. If it will be your second credo it will require twice more, thrice if 3rd credo. Stats will correspond to credo specializaion and it's hardness
4. Special item for starting credo.
Another limitation that will require special item that can be hardly crafted or looted in dungeons. As a gameplay limiter for doing lot credos.
5. Rebuild credo tree.
It will be simpler to make credos if there will be no need of making lot of excess credos you dont even need. For example you dont need to be forager or lumberjack to become a blacksmith. It only need to require quarryman and miner
I also will be glad if other players will discuss or argue their versions.