Honestly, I couldn't tell you a better interface as S-Gear. It's just brilliant - simply because you can see *all* relevant parameters of a patch at once whereas adjusting parameters of different blocks is turning into a massive clickfest with HXN (and obviously Amplitube, at least for the most part, too), let alone the incredibly bad "sweet" spot when it switches between scrolling and parameter adjustment.
Now, quite obviously, HXN is *way* more complexed, but unlike on the hardware, you often don't need all that complexity as things such as using snapshots (let alone stomps, which is just pretty much impossible) aren't designed to be used within the plugin.
I could think of some possibly easy to realize things which would improve the situation, but apparently all things UI are cast in stone in HX land.
Fwiw, almost forgot about it: regarding the UI, Guitar Rig is possibly the best (even if NI sucks as much as it gets as a company). You can create incredibly complexed patches, too (in fact, possibly more complexed than with HXN) but you can as well collapse things you don't need and expand those you want to adjust, so all relevant parameters might be visible simultaneously.
I mean, while I could still think of a lot of improvements, regarding quick editing, there's absolutely *no* way HXN could even remotely compete with this:
View attachment 23742
All parameters of a sort of typical patch at a glance. Scrollwheel support works as expected, too. Just excellent.