Policy routing is very cumbersome adding all directly connected subnets to main table manually. Mikrotik should have local table lookup to make it easy.
I agree that the policy routing with mangle table is quite cumbersome (route-map is so handy in Cisco). I've never been successful trying to set up a "management VRF" for instance, because ROS just doesn't want to look into a VRF routing table when originating management traffic packets.
However, if you were to just place all connected routes into all tables (as in this feature request), that would horribly break the entire concept of private routing tables. You may very well be splitting up a router such that interfaces 1&2 are in routing table 1 and interfaces 3,4,&5 are in routing table 2. It would be frustrating if after doing this, all 5 ports could still see each other.