Don't see any major problems with that - you need to remember that logically, the APs connect directly to the controller (regardless of what's in between - layer 2 or layer 3) and all wireless traffic will first 'touch' the wired network at the point where the controller is physically connected to the network.
So, in your diagram, a wireless client will associate with the AP and get an IP address (via DHCP I assume) which is associated with the Layer 2 VLAN 451. When they send data, this will be encapsulated by the AP in LWAPP and sent over the network inbetween to the WLC 4402. The 4402 will then unencapsulate (?) the traffic and send it out of whichever port you've configured onto it's local LAN with an 802.1q header stating that this traffic is in VLAN 451. Whether or not this traffic will then be able to get to where it's supposed to be going is dependent upon how you've configured VLAN 451 on the WLC's local LAN (not the remote AP's!).
If your layer 3 link between the routers is low speed, then you'll probably want to be looking at 1030 REAPs rather than fully lightweight APs. Minimum recommended bandwidth in this case between the routers is 2Mbps.
