Well, there are always other troops that can be trained.
Not everyone is supposed to be trainable.
Among other things, levels will be even higher in 0.8.
E.g., Elintoran Rangers are lvl 48 (Elintoran Crimson Ranger are lvl 60), Bakhal Seasoned Warriors are lvl 46 (Bakhal Champions are lvl 60), though there are only a few of such un-trainable troops.
Also I buffed xp multipliers to make them closer to Native values (in Perisno 0.7 they are much smaller).
Also prisoner rescuing has been changed.
Neither you, nor other parties will generally be able to recruit former prisoners from hostile factions (e.g. if a demon worshipers party defeats a band om Amazons who have Eagle knights among their prisoners, they will not recruit them, but rather keep them as prisoners).
Also recruitment will depend on your level, on a rescued prisoner's level, on your relation with the faction, on your persuasion (which will have more uses in 0.8 than in 0.7).
You will eventually be able to recruit even the best troops that you rescued (no hard cap like in PoP), but only if you are a good persuader, warrior and are in positive relations with their faction.