If the only criticism is that "I don't want all those lines on my minimap", it seems to me to be an awesome idea so far. It aids teamwork, which is hugely important, and shouldn't reduce the functionality of the minimap either. It's a simple matter of functionality and teamwork over aesthetics.
The problem I can see here is that there might be conflicting ideas of where the numbers are located (that already happened in this thread).
First of all, I strongly believe a consensus would develop, and secondly, nothing is keeping you from filling in the blocks with numbers in one of the grid spaces, preferably in an obscure part of the map, as shown below:
Pretty much every map has an 'obscure' area that could contain this 'legend box'.
Maybe you could make the minimap type an option, with one with keypad lines, one with a normal grid, and one with just the numbers from the grid for you grid-haters out there.
Disagree. A teamwork/communication tool needs to be consistent, or it loses much of its usefulness. Imagine this conversation:
Commander: Squad 3 and 4, I'm rallying you to defend the West Outpost. I'm gonna need Squad 3 there and Squad 4 to set up an ambush position at Charlie 3-4. Watch for enemy tank interdiction flights in the area around Bravo 3.
Squad 3 SL: Roger.
Squad 4 SL: What?
Commander: I said, I need you to head over to... Charlie 3-4 to ambush an expected enemy thrust. You also need to watch for dive bomb--
Squad 4 SL: Where's Bravo 3, my map doesn't say?
Commander:Oh, damn. Eh... OK... {thinking pause} if you open your map, there's a ravine south of the West Outpost. To its right there's a road...
Of course you can just implement the compass from PR (with 360 marked on it degrees), but I feel the grid system fits the mod better.
Better yet, implement both.