Is there a reason why I can only vote on 30 suggested edits per day? I don't think there is a real problem that more votes are abused or something like that. But every time, I reach this limit and then I stop voting, although it would be good for the community if suggested edits were accepted or rejected as fast as possible.
Suggested edit votes are limited to spread the load. That's good for the site, because it allows more people to influence the vetting and spot good or bad trends. It's also good for you: after 30 edits, go and do something else, like check on the flags, or go pile on the close/reopen votes, or look for unanswered questions, or ponder a programming puzzle, or think about science… or get a life¹!
I have to say that if you are going through 30 votes in 10 minutes, you're not doing this seriously. If you mean this literally, that's 20 seconds on average. A lot of edits can be decided in less than that, but there are quite a few that require more (that hyperlink fix: is it truly a fix and not a spam injection? That typo in example code: does the fixed code actually work? That reformatting job: did it do nothing more than reformatting? That retagging: is the new tag really appropriate?). A lot of suggested edits don't go all the way. Take time to improve them! Did the editor remember to improve the title as well as the body? Now that the code has been reformatted, can the English be improved? Are these really the right tags for this question? And sometimes there are other things you might do, especially for question edits: is it worth polishing this turd, or should you vote to close? Or leave a comment telling the asker to post more information? And, maybe, answer a question now and then.
[This paragraph was written back when it took 10k rep to browse the queue and the approve/reject quota was 30/day.] I do often burn through 30 edits in a day, but I see the limit as telling me to move on to other things. Especially since 30 recorded approvals/rejections means a lot more than 30 evaluated suggestions, if you take the time to improve a lot of them. I'd rather have more eyeballs. There are are currently about 1500 users with 10k rep, but of course many don't do any reviewing. I would prefer to lower the reputation threshold: open the queue to all ~2000 users with 8k rep, or maybe all ~2800 users with 6k rep. With the double vetting on SO, I don't think there would be any problem. (I'd be fine with lowering the threshold on other sites, but the volume doesn't require it — even SU's average is well below 30/day.)
Now that the review quota has been raised to 50/day (not counting Improve), I find that it's a lot to fit in a day. After that many, it's hard to still do the job seriously. I really don't want the quota to be raised again, I would prefer it brought back to 30/day, and instead to see more incentive for 5kers to review suggested edits. We need more eyes! There are about 5000 users with 5k rep, who can browse the queue. There are about 1000 suggestions on a weekday, i.e. we need 2000 reviews. If 1 in 5 eligible user reviews TWO (2) suggestions per day on average, we'll stay on top of the queue.
¹ Do what I say, not what I do.