[BRAINSTORMING] How would we design a "Main Battle Tank" Champion?

No, I don't mean a tanky Champion like Alistar. I mean something like the above: the M1 Abrams Main Battle Tank. 120mm high-velocity cannon, composite armor that's about as tough as 600mm of steel, and it can reach speeds of up to 72 km/h. Now that's a killing machine.

So here's a thought: How would we make a "Champion" that's basically a Runeterra version of an M1 Abrams?

I haven't got all the answers, but here are at least some thoughts I have. Note that they're not set in stone, so take it with a grain of salt.

• This Battletank would be designed for Yordles, so it isn't as big as a house. It'd more be the size of, say, a horse.

• This Battletank is a prototype made by the same crew that built Corki's ROFL-copter.
• The Battletank would be a ranged Champion that's slow, but sturdy, and good at sieges. In team fights, however, it's vulnerable to being outflanked.
• Compared to other ADCs, this Battletank would rely less on AS and more on hitting hard with each shot fired.

That'd be my starting approach, at least. What would yours be?