A 737-800 can barely do Bristol-Canary Islands non-stop with unfavourable airport and en-route weather conditions.
Ryanair operates at least 6 x weekly from BRS to the Canaries with B 737-800s and have been for a number of years. Do they have problems at times? I haven't heard on the grapevine that it's a major issue for them.
Worth noting that the BM MXP service it not on sale beyond 21 March; all other BM routes are on sale until the end of October so can only assume this route will cease to operate after that date...
Is it only a matter of time before EZY eyes this route to take on FR BGY?
In the meantime, notably, the CWL BE service has gone to 4 x weekly during the summer.
In 2008 and 2009 Ryanair and easyJet did go head to head on daily flights to BGY and MXP respectively. easyJet then pulled out and Ryanair gradually reduced BGY to the point where it's now just a 3 x weekly summer service.
MXP is a route that I'm very surprised easyJet has not brought back. They introduced Basel this winter at 4 x weekly (2 x weekly in January) then back to 4 x weekly at the beginning of February and on through the summer. Stats suggest that the route is not up to easyJet's usual BRS loads, and whenever I've looked fares have not been expensive either.
Venice which easyJet is bringing back in March at 4 x weekly (using Venice-based aircraft) was flown until 2009. It will go against Ryanair's version of Venice at Treviso which would be a similar scenario if easyJet flew MXP against Ryanair's BGY.