I think there should not be a level limit. Powerleveling is one of the joys in life. Besides, it took me almost a year to get Tashiro to level 93.
All right, I started Sapphire for my soon-to-be famous all-blaziken run! (of course. :D)
I find that torchic is a good starter in Sapphire because double kick defeats Team Aqua's carvanha easily. Blaze kick later on is excellent for zubat and friends.
So, I finally found a decent female torchic. I named her Passion and gave her a few attack EVs because her attack was running low. She was at least level 6 before I fought Brendan and I still almost lost. =/ Oh well; the potion comes in handy sometimes!
I helped Wally catch his ralts and am about to challenge Petalburg Woods. Wish me luck!
Well, I got through Petalburg woods and defeated all the trainers around Rustboro.
My combusken was level 17 by the time I got to Roxanne. Double kick wiped her out before school today. =)
I'm currently defeating the trainers in Brawly's gym, going by my "defeat every trainer possible and level up fast" idea. After Brawly, I'm going to head back to Rustboro to get HM cut. I can't believe I forgot it again.
I've decided that I will have a blaziken before Winona, she will know slash before the twins, and she will know sky uppercut before the elite four the first time.
MEGA edit: I have beaten the elite four for the first time.
I had a blaziken before Meteor Falls and she knew sky uppercut before the twins.
By the time she defeated Steven's cradily, she was level 68.
Wallace was a breeze, though Kyogre was hard. Thankfully, hydro pump missed twice, but a calm minded ice beam isn't fun even for a fire type.
I also managed to capture a modest kyogre. ^_^
The elite four was easy until Drake. I kept slashing his salamence until it fainted.
Steven was easier, though I had to soft reset a few times.
This was immensely fun and I enjoyed it a lot! Now I've learned the consequences of training a full team!
I also got an adamant beldum without soft resetting. ^_^