I'm happy with the general Openvpn improvements in ROS, still it has a limitation that makes a scenario with multiple mobile clients (one of the main uses for Openvpn) hard to manage: I cannot push openvpn parameters (mostly routes) to the clients from a Mikrotik server.
This makes it hard to manage confg changes because if for example I add a network on the server side, and want to teach the clients about that new network that has to be routed through the vpn, I have to edit every client config file with a new "route x.x.x.x" config line.
With the pushable config lines, it's just a matter of adding a "push route x.x.x.x" to the server config, and all the clients will get the new route.