I think the reaction was to be expected, really. Every relaunch has had negative comments on Facebook. Women (mainly) went from screaming 'Bring back Ben and Fiona' to 'Bring back Kate and Dan' which has now turned into 'Bring back Lorraine and Aled' ...thus the fans of Ben have obviously disappeared
It's laughable that people are chiming in saying 'Bring back Daybreak', too.
Would the obvious thing to do not to have introduced the new presenters in a longer transition phase, so that there isn't the abrupt change? During the Garraway-Lobb era, Lorraine could have had an increasingly-prominent position as one of the Daybreak team long before she was named co-host. Or equally could Ben Shephard or Sean Fletcher not have been introduced as a contributor late last year, including perhaps as semi-regular presenters/ fill-ins? Just as Aled and Lorraine could have been involved somehow this morning... not because it actually achieves anything substantively, but it helps allay any sense that 'person X has been forced out' or 'I don't like person Y' when they've just joined. To take another leaf from the Americans, the promotions of nearly all of the current crop of presenters on Today and Good Morning America were introduced over many months or years as occasional fill-ins before eventually taking main positions - both broadcasters go to some length to develop onscreen 'talent' over time.
The BBC also adopts this model on Breakfast. ITV, however, seem pretty hellbent on hiring from outside the ITV family - Crosby, Chiles, Bleakley, Lobb, Jones, Reid, Fletcher, Hawkins, Barbet, Singh etc. were all prominent names from non-ITV accomplishments, and were all brand new to the ITV family upon joining the breakfast programmes. Lorraine Kelly (and the return of Ben Shephard) are the only examples that spring to mind of ITV using in-house talent for the relaunches on a permanent basis, and Shephard's just returned after years at Sky.
To be blunt, Ranvir Singh and Kate Garraway are unlikely to succeed Susanna or Charlotte in the long-term if the current lineup doesn't work out. An American broadcaster would be unlikely to keep them in those positions, in that scenario - and instead look to lower-profile, talented (if not yet perfected) presenters who could be put in the B-roles in training. ABC have just done that with Amy Robach and Ginger Zee (and brought in Michael Strahan and Toni Reali from elsewhere in the vast ABC family) following two sudden departures, and ratings have gone up; while Savannah Guthrie perhaps didn't have long enough to become accustomed with Today viewers before replacing Ann Curry, it's unthinkable at this point that Matt Lauer's replacement won't be from someone in the Today (or at the very least NBC) family - Carson Daly, or Willie Geist, who have smaller roles and are Matt's primary back ups.
Presenters are not the thing that makes a programme work - but they can be what makes it fail (case in point, Today and GMA). If viewers this morning didn't warm to Susanna Reid, I'm betting they're less likely to tune in tomorrow than a viewer who didn't warm to the content. You can hate the US broadcasts - and Today and GMA are mostly useless - but between them they make $750m+ and fund the massive news divisions. Only now do ITV seem to be trying to learn the lessons from them, and I just hope they go far enough*.
*I don't mean the broadcast should become too American, but they should observe how the American broadcasters relate to viewers and change their offering as a result.