It's a tricky one. If we're going for an English candidate, there are only three or four serious candidates, but all come with caveats.
Sean Edwards is a serial winner who has been a massive part of Wales and now France's success. He is a world class defence coach, but there's no actual evidence to suggest he is more than that. His track record is good enough to suggest he could be and I'd be open to giving it a try. However, being the head honcho and the guy who the buck stops with is a very different role. Hard to say how well he'd cope with that and how he'd translate his success as a defence coach across all other aspects of a head coach remit.
I like Rob Baxter a lot. He comes across as a fair and likeable guy who seems very good at building a culture and bringing people along with him - both players and coaches. However, I can't say I have ever particularly enjoyed watching Exeter play. They perfected a style that won them domestic and European honours, but it wasn't pretty and as it's become less successful, they haven't really adapted. I could definitely get behind him if he was given a really good coaching team.
Andy Farrell is doing very well with Ireland, but there's no denying that Ireland benefit hugely from the central contract system and the ability to draw the significant majority of their starting XV from arguably the best club side in Europe. It's hard to gauge how much credit Farrell deserves and he is definitely tainted by his role in the 2015 disaster.
Steve Borthwick is probably the most palatable candidate IMO. He's doing a great job at Tigers and he is the only a candidate with genuine, up to date*, understanding of both the international and domestic game. If he wins the league with Tigers and can continue that success next season he'll be at the head of the queue. The fact that he's a former England captain can't hurt either.
*Edwards has obviously coached in the Premiership but not for a long time.