The Baikal concept is my idea of a practical booster return system. A modified URM-1 module with a swing wing, a small air-breathing engine and UAV controls to provide cross-range capability to allow flight to a recovery airstrip. If the engine module could be made easily decoupled by bolted structural sections, graylock couplings for piping connections and plug-in electrical connectors for controls & instrument loops, the Baikal could be rapidly turned around by fitting a new engine and full systems retesting before going back into the inventory. The disconnected engine module then goes to refurb for inspection, boroscope checks, clean-up/de-coking and a test burn before going back into the pool.
SpaceX has persisted with their powered stack descent and tripod landing, and have managed to land on a marine barge (an impressive achievement), but I still don't like the concept. Its too hit or miss, and a failed landing scraps the whole stack. I'm also not convinced that a powered vertical ascent isn't a lot of thermal strain on the engine bay. I'd much rather a UAV-style return and aircraft landing, as its gentler on the hardware and is far more fault-tolerant (depending on fuel supply, you can stack the cores in a holding pattern while you bring them home).