YOU are telling people to use mixing services such as coinjoin which are already considered by regulators as suspicious enough to delegate via active regulation that services to put funds on watchlists and investigate if it reaches thresholds
So, let me get this straight. You notice that regulators are hostile on mixing solutions such as coinjoin, yet you're somehow under the impression that they will not be hostile on mixing via mining pools. Makes sense! 
thus im saying use ways that are currently not in regulators remit and currently regulators have deemed mining as NOT A MSB
Your proposal is not currently in regulators' remit, because first of all it is one of the dumbest ideas I've ever heard, and second, because there is no implementation and usage due to the former. Be certain that if enough people started mixing through mining pools, regulators would deem it as suspicious and enact it as illicit, just as with coinjoins.google the definition of MSB
google the definition of VASP
google the definition of payment facilitators
routing comes under the banner of being a VASP/MSB/payment facilitator
then google the regulations in regards to cryptocurrency(VA)
and them look at how they are aware that there are payment facilitators/MSB/vasp not just on mainnet but that routing is in the definition
ill give you a few highlights. but i wont spoon feed you like a baby, you should learn to do your own research.. you are old enough to feed yourself
https://www.fatf-gafi.org/content/dam/fatf-gafi/guidance/Updated-Guidance-VA-VASP.pdf
Quote
85. AML/CFT regulations will apply to covered VA activities and VASPs, regardless of
the type of VA involved in the financial activity (e.g., a VASP that uses or offers AECs
to another person for various financial transactions), the underlying technology
(e.g., whether it uses mainnet or the use of embedded layering or other scaling
solutions), or the additional services that the platform potentially incorporates
(such as a mixer or tumbler or other potential features for obfuscation)
the type of VA involved in the financial activity (e.g., a VASP that uses or offers AECs
to another person for various financial transactions), the underlying technology
(e.g., whether it uses mainnet or the use of embedded layering or other scaling
solutions), or the additional services that the platform potentially incorporates
(such as a mixer or tumbler or other potential features for obfuscation)