The thing is temptation is always around, non mages face temptations all the time, it's that thing inside us that says no this is wrong. I wont do that. Granted it would be harder to resist a demon than robbing a bank to feed your family, but there are mages strong enough to resist. It's just not fair to treat everyone the same.
Temptation will always be around. For everyone. Temptation takes many forms. But I think reducing the squeeze on mages will go a long way toward preventing abominations. Demons tend to prey on the distressed and weak. If more was done to integrate mages into society on a normal level and the stigma were to disappear, I think far fewer mages would succumb to demonic suggestion. If the stigma of magic was gone, even mages with a problem, like a sick child perhaps, would be able to turn to the greater resources of the Circle for help rather than resort to forbidden magic. I believe a compromise is possible.
In my ideal scenario, mages are registered and sent to a different kind of school than other kids but not removed from their families. The Templars would be a more widespread authority - not greater in terms of jurisdiction but more out there, like a special kind of police force. I'd also have the Order's attention steered toward detecting bad magic being used against all people by making phylacteries standard for everyone rather than just as a tattle rattle for mages. All citizens would have one - because in my assumption, the phylactery of anyone who is experience magic being used against them will light up. For mages, having magic used against them may not appear differently in the vial from their own usage of magic, so mandates for no magic use except in self defense and/or in production of their trade at approved times and places would set perameters for when it might be expected and when it might indicate something untoward was occurring.
There are also glyphs and runes that can affect magic and we use them in combat. Why not use them to protect areas as well? Magic-proof important places, like the Chantry or medical facilities and town halls. And the Order would more than just a Mage-keeping force - they'd investigate instances of illegal use of magic, provide protection -of course - to sensitive areas and people, and help devise ways of detecting and preventing magic from being used as a weapon. But they would do this not from the position of locking mages up "just in case" or as mages being "the bad guy" but rather as a benefit to all - mages too. Here's the humdinger: even mages could be in the Order, helping to fight against bad magic.
I know it's idealistic but that's what I see as a compromise. Monitoring and safeguards for the Templars' peace of mind and freedom for mages on par with everyone else. I think the whole reason Thedas is in the mess it's in is because of the "Us vs. Them" mindset the rest of the world has against mages and the violence and death that have occurred as a result is responsible for what's going on now. But that's me.