Currently we have to do some overly complicated stuff with bridge filters in order to set priority for MPLS frames. It looks from the OSPF module in v7beta that you are making some enhancements for MPLS L3 VPN (Domain ID and Domain Tag support) and so I am hopeful that while this is happening you might be able to fix another few long-standing issues.
One of the problems is that MPLS FastPath is on for all hardware devices (meaning everything except CHR) and there is no on/off switch. When it is on, the VLAN priority does not get set properly for an packet with non-zero MPLS EXP bits set by the previous device (this is supposed to happen automatically). This feature works properly only with CHR since CHR has no FastPath. For all hardware devices, we have had to add otherwise unnecessary bridges to interfaces plus otherwise unnecessary bridge filter rules to coax MPLS FastPath to turn off in order to get VLAN priority properly set for MPLS frames. This bridges and filter rules would not be needed at all if there was a place to disable MPLS FastPath in the device globally.
Also, I would really appreciate having MPLS mangle available somehow. Currently to do QoS over fixed-rate links with MPLS we have to use bridge filter rules to mark the packets based on the ingress-priority of the packet, which again means extra bridges that are otherwise unnecessary. It would be great to have a way of matching MPLS frames to apply packet marks.