I suspect that you're going to see similar results for any filesystem when you have to run a full check of the filesystem. If you have 1,000,000 inodes in use, it doesn't really matter how they're organized if you have to check the consistency of all of them. Any way you cut it, you're going to be touching 1,000,000 files.
The things that will significantly speed this up are faster disks and more spindles. If you need 1.2 TB, you'll get significantly better performance out of 8× 300 GB SAS drives in RAID 10 than you will out of a single 1.2 TB SATA drive, independent of the filesystem. Sure, it will cost you more, but what does your downtime cost you? It still won't prevent filesystem errors, but it will reduce the recovery time.
Something else to consider is whether the data on the failed volume changes very much. If it's mostly static and you have a good backup, it may be faster to re-
mkfs the volume and restore from backup. You risk losing recent changes, but again, you have to weigh this against the cost of downtime.