I see the best utility for this as a duo situation. Lets say a RDM and a WAR fighting mobs that do between 70 to 120 damage on normal strikes. With Phalanx and Regen III/IV on the WAR, you effectively cut down on the amount of support the WAR needs to get by. And free's the RDM up to do what ever.

In end game situation I suppose it would allow melee to recover at a medium pace after getting hit from AOE's as long as there not being spammed. They might be helpful in keeping pace with damage in a RDM main heal situation, tho I wouldn't put much stock in that. The way I've seen it, getting a guy back up to max hp is imperative in end game fights. Mobs do such massive damage I've seen ppl go down when they were in the white with only 5 to 10 % of their hp gone.