One one hand I have to agree with Greybeard, he speaks the truth but I also have to agree with Bob/Fla and the Old06. I suppose that if you want just another lever action that is neither difficult or a challenge to shoot, then you might just as well get the 45-70. It will do anything the 450 Marlin will do, so the choice between those two cartridges is easy to make. One the other hand, you also mentioned the 444, my favorite.
You didn't say whether you reload - that's where the 444 can come to the fore (no joke). What you can handload to in the 444 would hurt you in the 45-70, but I won't advocate taking on a project to learn a new caliber unless you are up to and into that fun part of shooting and hunting.
And, of course, since you mentioned the Marlin, then I will have to recommend the 1985 CB for its light weight, ease of carry and handling (I kin tellya alla that 'cause I played with one this weekend). Notice I said 'ease of handling' - it's a dang good field piece. I compared the 26" Marlin to a custom 26" 94AE and found the Marlin running at about 7 lbs, scope and all (unloaded). And, with a good scope, they are murderously accurate. So, there ya go. HTH. Mikey.