I think it's the fact that Adam wants to work 16 hour days.
The decision to make Adam front all of the Sky election coverage will not have been made by Adam on his own. The powers that be at Sky decided in conjuction with Adam that he was to do that, and that was the wrong decision.
Skys political team is the best imo.
When the prime ministerial debates were being discussed, specifically who was going to chair the debates for each broadcaster, only one name came up for Sky - Adam Boulton. For the BBC, four names were suggested (Dimbleby, Paxo, Huw Edwards and Andrew Marr), all being big names, with a history of being able to carry out that role. Sky's politial team would improve greatly if they could poach just one of those names to support Adam (not replace him).
Jon Craig is chief political correspondent and along with Joey Jones they deserve more airtime.
They may have a good team underneath Boulton, but none of them are able to shine while he is presenting every possible second of the coverage - Boulton was the face of the Sky News elections coverage. I couldn't name a sole face of the elections coverage on BBC / ITV / C4. With the BBC, Dimbleby was the face of the election results, and the debate, but apart from that he has been in the background, with others taking the lead and making significant contributions to the BBC's overall coverage.