I do not think it is unreasonable to teach Trail & Peel, as it should help to solidify the 'concept' of Peel & Trail.
I've never heard of the call 'Horseshoe Bend' (it must be a *very* old A1 call, so old that it was never on the A1 list). 'Cross Horseshoe Turn' (Ends Cross Clover as Centers 1/4 In & Cross Trail Thru) was once on the C2 list, and may be a good choice for an Advanced workshop.
Trail & Peel was removed from the list because it was infrequently used, and does not 'flow' as well as Peel & Trail. Perhaps another reason it was removed is because from a Mini-Wave Box, it was choreographically equivalent to Box|Split Recycle.