Yea I just started using touchpads, and before I wouldn't have thought much difference than mouse, but after playing some other roguelikes, including tome and a nethack port...
The big deal is in touchpad on smaller displays at least, you can't expect the same precision.
I think it will be very difficult to expect a player to essentially hit a tile with finger all the time. And I think with how roguelikes can have so much going wrong, and only 1-2 ways out alive, I can really see how I under appreciated my mouse's precision.
I think doing feedback-while-touched but not rumble just have it "pop-up" and maybe highlight blue it or something so you know what you're clicking before choosing targets and using an ability.
Also you should probably do less skill bars, and just have an easy way to rotate through multiples, like a static page button.
The main reason for less skill bars, I think, is put noticed enemies, and perhaps items, as pop-out tabs that essentially aliases to their entities, and can be touched instead. Combat in a roguelike tablet when fully surrounded can be tough unless you have player use keyboard -----
and I strongly hope you guys can figure out a solution that doesn't make use of software-keyboard on the devices. I do think support should of course be on hardware (or if user insists) as well as mouse support. Ideally I think one could play this unconnected to keyboard, with little changes to keep layout clean for touch. Plug in keyboard&mouse, and if the player so wishes, interface goes to our desktop tome setup, with little or no hassle.
I do think though if a serious roguelike went to tablet or phone it would need an interface change, rethinking most likely many things.(entities in game cannot be clicked for any reason. Targetting is done by choosing action, then enemies are highlighted one by one as player taps anywhere on screen but X button. When correct target, hold finger down anywhere. And with ground targets, or probably all targets, think about using a way perhaps of zooming into an area of interest without completely replacing the rest of map. and even with ground, the thought of hitting tiles still gives me nightmares on those things. I would almost think for things like that and movement put a transparant number pad that can be moved itself after long-finger-down, especially if doing something like making entities unclickable (you could still run into them for melee, and from experience most of the time if crowded instead of zooming image with fingers, and tapping them all, I would just give up half my screen for a inscreen keyboard so I could get past them and turn off the keyboard.
touch screen can also be more benefit to some interfaces. Unfortunately tome comes from an ideology of no interface lol.
but for example, a button for walking to a direction a set number of times. instead of making it bring up a dialog asking for a number, just have it display a number that increases if tapped, decreases if double-tap, and resets if held down. if you use a move button and that has a number on it, move that many and reset it.
Or basically confirm each action user takes. That could be done in a way I think that isn't much more in the way that requiring an additional click after target, if done well.
I think it would be amazing if tome got onto a portable though, and this is a fun topic for me :)