Greetings.
I'm a somewhat proud owner of a Windows 8 hybrid tablet, and I found it quite surprising that, in its existing state, OpenXCom is tablet-friendly to an unexpected extent.
Menus respond perfectly to touch input, buttons are large so that missing is difficult, and even in Battlescape it's surprisingly easy to get around (though right-click-drag scrolling doesn't work for some reason, and left-click-drag denies the targeting preview, but it's workable). The only times you ever actually need to bring up the keyboard are when you're building a new base, and when you're saving a game.
But, typing a name of the savegame is one thing. A completely baffling oversight, however, is the lack of a "save game" button. Even if you're overwriting an existing save (playing "ironman", as it were), you still need that keyboard up to press "enter" in order to save.
When creating a new base there is a similar problem, though I guess it's expected. However, perhaps slapping a default name on the base according to its region, and adding a "confirm" button would be feasible? Not that it's actually required - the onscreen keyboard is a touch away and base-building is a fairly infrequent task - but it could be a neat thing to have.
There are probably similar issues elsewhere, where you can enter a text field with a mouseclick or touch, but can't back out of text entry without keyboard input. But those are fairly rare and not essential.
All in all, I was rather surprised at how X-Com's UI design would happen to be perfectly playable without a physical keyboard, with only a few hiccups.
Core of the suggestion:
Add a "Save Game" button to the save game screen, so that a game can be saved without pressing the enter key when a physical keyboard is unavailable.
Add a "Confirm" button and a (optional?) default name to the Base Creation dialogue, for the same purpose.
And before I forget, thanks for breathing new life into an old classic. ^_^