Converting hybrid back to conventional power remains a rarity in the UK, and that only happened to Optare products which are notoriously unrealiable.
As for the E400H (and indeed B5LH and NRM), I will be amazed if they do anything other than replacing the battery packs when the time come. To replace the powertrain completely takes far too much effort, and costs too much for a bus that if well past the halfway point of service life, to make it worthwhile.
And as for the trial result itself, it is hardly surprising given how much hit the air-cond system takes out the efficiency. Having said that, this also affect pure electric buses in the same way. For this reason, I do think that the virtual electric concept i.e. hybrid bus with opportunity charging, like the B5LHC, has a lot more to go for. However, to make this work, it needs a very comprehensive planning to strategically place charging stations at locations where buses are likely to stand for a relatively long spell (3+ mins) to make the system works to its best efficiency. That said, I am skeptic to see this ever happen in HK.
