Firstly - you are only referring to Classifications. The handicaps table is the same for all bow styles (except where the target face used dictates otherwise - but a longbow can still use inner-ten scoring if desired!)
Indoor classifications are still regarded as something less than important - you only have to look at the titles of the levels, with all the romance of a concrete lock-up. When we were looking at the classification levels a few years back, the feeling on OpsCom was that no one is really interested in indoor classifications (and that to rename the levels would, in some way, detract from the prestige of the outdoor ones). There was also the perennial argument that there was not enough data to set appropriate levels for ELB or Barebow - so we should not bother. In the end, we concentrated on the outdoor levels, saying we would look at indoor when things had settled down. Well (apart from proof reading) things have settled down, so perhaps now is the time to get the indoor levels properly examined for all recognised bowstyles, and renamed. The first stage would be to approach the Operations Committee and propose this; then gather sufficient data.