What good is something that is hard to kill if it can be ignored? Gotta be able to cause damage each round over and over or it's just a nora sink and ignored. You should read what we've been discussing about Aspect and using Spare Parts in the Look Who's Back thread here: http://forums.poxnora.com/index.php?threads/look-whos-back-post-here-if-returning-or-just-migrated-from-soe.1693/page-3 Start reading at post 42 on page 3. I've been working on an Angels and Spirits BG so that with Spare Parts many of the "both abilities" are transferred due to being same race. The other nice thing about this, is most Angels/Spirits have really good upgrade abilities to transfer as well. Someone also mentions a construct BG using spare parts, especially since we have melt down to control how and when things are transferred, as well as get a nora refund for it.
Angel Spirit BG's have long existed. The most recent thematic work has made it much more viable however. I remember doing both IS/KF and IS/FW with much success around the release of Vashal Vicar. Angel of Mercy has Improve Range which is just awesome.