The 30-30 was doing what it needed to do LONG before many of the "newer, high performance" calibers were even considered. And the Lever action rifle is an excellent design to use as a fast handling, all around good rifle for many chores.
Performance should be judged by accuracy first. Especially over a variety of conditions. Heat, cold, etc. You can have the fastest,, but maybe not as accurate as it can be. And performance is a subjective discussion by itself.
Hunting performance? Paper punching performance? Tin can plinking performance? Training performance?
None of it matters if you can't hit accurately.
As for "weak" brass,, the 30-30 isn't as bad as some,, (say 38-40) nor as good as some, (say 30-06 mil-surp,). I've converted a bunch of it to 7x30 waters,,, after it had been loaded more than once,, and shot it several times as 7x30 waters with only occasional splits etc. No more or no less than other calibers. But my stuff was loaded for accuracy & not stressed with "hotter" loads.
Find a good bullet that'll do what you seek,, then load it for accuracy & don't look back.
BTW; if you think you need high velocity performance,, consider how many handgun hunters,, using revolvers, cast bullets, and loads around 1000 to 1400 fps have taken truly BIG game animals with one shot kills. If you want to read about such stuff, may I suggest you read about a friend of mine. American Handgunner writer,, Jeff "Tank" Hoover just published a 2-part story about an african safari that Dick Thompson took recently. He only used handguns,, cast bullets, and took several big animals including a Cape Buff. Do a search & read about it. Dick tells the story quite well, and Tank allows him to share it his way.
Performance is more than velocity.