I'll look into togekiss.
do you think earthquake would be a viable replacement for crunch? Is ice punch also useful enough? I'm still on the fence. Lucario is so versatile!
Also what's your view on togekiss creating a 3 times rock weakness on my team? should I be concerned about stealth rock?
I like to use the team magma team builder to even out my teams typings. But to be honest, past that I'm not very good at creating evened out teams.
All Earthquake really does for it is let you hit Aegislash super-effectively without having to worry about King's Shield. Mega Lucario's Adaptability STABs (mainly Close Combat) hit just about everything Earthquake does as hard or harder. So personally I'd rather use Crunch over Earthquake. Or even Iron Tail like Platinum suggested. I'd also suggest keeping Ice Punch; Ice is such a useful offensive type and Ice Punch allows it to smash several 'mons that resist Fighting and aren't hit hard enough by Crunch or Iron Tail (which is also inaccurate) like Dragonite, Gliscor, Landorus, Roserade, non-Mega Venusaur, Amoongus, Staraptor, etc without having to switch out. You can also snipe Garchomp with Ice Punch and save a PP for Close Combat.
I don't think that you have to worry
too much about half your team being Rock weak since Stealth is rare in Battle Spot and Lucario and Feraligatr beat enough Rock types and Rock wielding pokes for you. But if it still bugs you you could use Gengar in place of Togekiss. It lets you keep your Ground/Fighting resist (or immunity rather) while still having good offensive presence, particularly without the need to set up.