Sarien's hires mode causes some behavioural glitches, and should be removed in favour of leaving these Scale2x-style graphical enhancements to the ScummVM backends, especially since it can be made optional at that point.
AGI is a fairly touchy engine, and really requires pixel-perfect rendering internally; the hires mode thus causes a few problems.
Here's a couple of screenshots from Space Quest 2 to demonstrate the kind of things that go wrong:
