Having been on a west (Clydebank)-bound Trident on the 60 right in the midst of the evening peak more than once, I'm not sure that fully converting it back to singles is a good idea, even with the associated cost savings of such a move. Same with the 60A, as that is also routinely rammed in the evening rush, even with Tridents being the overall dominant vehicle type. One hopes that with the incoming new stock, a major reshuffle takes place so that Geminis (both B7TLs & B9TLs) come to dominate both routes.
When it comes down to it, the vast majority of Tridents, as well as they have served the city and it's environs, are life expired and fit only for the scrappers. Only a select handful of the best examples are likely to even be considered for transfer elsewhere and even then I wouldn't bet on it happening. Just a matter of waiting and seeing what happens, as is always the way with this sorta thing...
Yeah, The One is a heck of a success story, the passenger numbers testifying to that.
If FiG were to replace the route's current E300s anytime soon, I'm not 100% sure what they'd go for. Something from Volvo/Wright like in the past would be nice and much better suited to the nature of the route (a la East Coast Buses' Eclipse 3-bodied B8RLEs), but something from A.D.L's range would be a far more likely choice, considering they've standardized on the latter since 2014.
PS - the B8RLE/Eclipse 3 talk is hypothetical and nothing but pure speculation on my part, so please don't take any of it seriously lol