Masterarminas, that Imperial Walker variant is pure genius. I take my hat off to you, sir. Ambles along at a gentle 4/6 speed, but has the incredible mobility of a 'Mech through all kinds of terrain. Just think about the possibilities -- through woods, under water, even up steep slopes!
As for artillery, I'm a huge fan. Sadly, only Clan Arrow IV launchers or Artillery Cannons (the short-barreled things) can squeeze onto a quad given the 14 crit max available (side torso plus center torso), at least in 3053. Once you have compact gyros, that still gives only 16 crits, which isn't enough for the heavier artillery pieces. The four legs make it seem like a far more stable firing platform than biped 'Mechs, but the rules-as-written just don't make it possible, at least not until the FedCom Civil War era, or the (re) introduction of Superheavy 'Mechs.
Now a Superheavy 'Mech with a Long Tom or two? Delicious. Pure cheese on rye bread.