lucarios fsmash has such huge range even if marth counters it, it wont even hit lucario.
Are you sure of this. I know Marth's counter has deceptive range, and I'm almost certain he's been able to hit me after a tippered fsmash before.
But, really, as long as you camp with AS and fsmash there's not much Marth can do. Make sure you charge your aura spheres or use them at high %. Marth can cancel BAS out with most of his moves. Bottom line: don't let Marth get on the inside. His dsmash and usmash have both received good buffs, and they can kill fairly early now. His utilt can kill as well, and his dtilt might outrange a few of our moves. Dancing blade ***** now, seriously. It's quick and easy damage for Marth, and it may send you offstage for an edgeguard. It also renews all of his moves. Marth has a lot of release grab setups, but luckily I don't think any of them will work on Lucario.
I wouldn't even try the FP chaingrab. Marth is floaty enough as is, and his upb can break through anything. Comes out on frame 1 and has invincibility for 4 frames. You could try to predict the upb and shield (in that case you'd be able to punish), but I still wouldn't mess with it.
What will Marth be using? Mainly dancing blade, fair, and fsmash to kill. Fair is still really good. Many say that Lucario's air game beats Marth's (which I'll agree to some extent), but I still don't think it's a good idea to go against his fair.
Stages. PLEASE don't go battlefield. Battlefield has been Marth's playground since Melee, and it's for good reason. Marth has all of his options open there - tippered smashes, SH aerials, etc. - so it's difficult to avoid him and camp. Take him to FD (where you can maximize AS spam), or to Yoshi's Island (which is always a good Lucario stage). Never take him to Norfair. Marth dominates everyone there.
To sum it up, Marth is faster and stronger than Lucario. His edge game is excellent, and his killing options are far superior to Lucario's. But, without a projectile, Marth is vulnerable to aura sphere. Controling Marth and keeping him out of range are key to this matchup. Once Marth is in close Lucario has few viable options.
I'd put it at 50-50 or 45-55 Marth.