As Dagger pointed out, one of NXT's charms is that the stars aren't as overexposed the way they are on the main roster. For instance, a full set of tapings, maybe 3 to 4 weeks worth of shows, may go by without us seeing Bobby Roode, Asuka or the Authors of Pain and that's fine as it is given that NXT is part of the WWE Network rather than a standard television show.
Does NXT NEED another hour? I don't think so but I am curious to see how Triple H and the NXT creative team is able to handle another hour. That's something a lot of fans have been curious about as it'd give us even more of an idea how the main roster product MIGHT or COULD be with Triple H ultimately being the final decision maker. Would they use the extra hour to feature more stars each week? Would they keep roughly the same number of stars each week by having more big matches that last longer? Of course, finding the answer to that question runs the risk of ending a charming component of the NXT product. If they ever decide to add another hour to the show, an example of a formula that could be used often could be having a 10 minute promo segment per hour, though not at the same time each week of course, with maybe a couple of 3 minute squash matches each hour, a few brief backstage promos that last a couple of minutes, maybe around a 30 minute match as the main event for each hour and still only feature the champions on the show every so often rather than each week. Various details would have to be worked out, such as deciding who on the roster are strong enough to deliver longer matches. I don't see NXT going to 2 hours anytime soon because what they're doing right now has been working for several years now.
As for an additional title, as Dagger also pointed out, the UK Championship is technically part of NXT at this time but it's anybody's guess how long that will be the case. If they added another title to the NXT roster, I think I'd prefer it if they moved the Cruiserweight Division from Raw and made it part of NXT. A lot of CW wrestlers work NXT house shows in the first place and the division itself would benefit, I have no doubt, from being under Triple H's control rather than Vince's.