I do think they could do with a GT analyst, someone who challenged/ won a GT.
In the pre-GCN days, Eurosport would bring Stephen Roche in for the in-studio segments during the GTs and obviously had Sean Kelly on the commentary. This seemed to work fine while it was a niche sport, as they had a very small core of commentators they could juggle, whereas now there are a lot more names and obviously you've got those who are linked to GCN and those who are contracted to Eurosport and those who have host broadcaster contracts for particular races and so you've got a lot to balance off. For a long time Eurosport got by with only Harmon and Kirby as PBP as they seldom needed more than 2 races simultaneously and any additional races they could just buy the hosts' highlights packages and broadcast on a delay with overdubbed commentary if no commentary in English was available.
On the PBP side, perhaps the smartest guy out there is Marty MacDonald - Marty has been a utility guy doing smaller races for host broadcasters and popping up occasionally for quite some time - you can see him on a bunch of obscure UCI Asia Tour races' highlights packages for example - but he's focused heavily on the women's races and become the de facto go-to guy for PBP on women's cycling, instead of being crowded out on minor men's races, and got himself a niche where he's the clear first choice on a large number of races.
On the analyst side, the big problem that they have when it comes to the stage racing/climbers side of things is that with GCN being based in the UK, the fact most of the UK's cycling interest has come from the track until very recently means that the number of genuine stage racers and GC riders they could choose for coverage are limited; most of the UK & Ireland stage racers are either still active (Yates, Yates, Carthy, Froome, TGH, Thomas) or are already involved in the coverage (Wiggins, York, Roche, Roche, Kelly) - with perhaps the sole obvious exception of Dan Martin. And of those, Wiggins doesn't really add much insight (but his being Bradley Wiggins is a good hook for the casual fan compared to any of the others), Stephen Roche is now a rarity, Sean Kelly usually doesn't appear in studio and Philippa York only appears sporadically. Nico Roche seems like he has potential from a race-reading point of view, but he needs a bit of coaxing out of his shell for the time being. And I dread to think how fawning and banter-tastic it will be when Geraint Thomas eventually inevitably joins the crew. On the other hand, Hugh Carthy I think would be really good.
Going to other Anglophone areas for stage racers has potential, but is still relatively limited. Most of the viable North Americans have chequered history (Hesjedal, Danielson, Leipheimer) or have alienated the GCN contingent (Horner). Australia gives us but two logical possibilities out of riders who are retired - but to be honest, Evans doesn't seem like the TV presenter type and Rogers is more boring than the 2013 Tour of Hainan with a soundtrack of Coldplay.