Currently MSO only allow to post once in 20 min, at-least for the beginners like me, instead of restricting the user from submitting it could be queued for a review and allowed to be posted based on the people judgement.
I can see your point of view, sincerely. You may have two genuine questions well written etc, and perhaps are fine to be in two questions and even going so far to say Stack would be happy with you doing this.
However, firstly (and harshly) the limit is there, and that's the way it is. The limit will be in place for many reasons, but the two obvious potential issues, which is why it wont likely be changed, are:
To stop people bashing out loads of questions because they are writing a script/website/etc but are not experienced developers so know very little and ask every step of the way.
Counter spam flooding, visit a forum and check the newest posts for a few hours, if you don't know what I mean.
While it's speculation to say this will bring spam and lots of bad questions flooding in one after the other, it's from experience that I know this will happen.
Even the same question posted a few times with the poster trying their luck with different tags, among other scenarios.
In fact what I see now shows there's currently a doorway for potential flood posting, where in PHP tag people post "How do I do this with an array", then soon after "How do I use this array to query". This sounds to me that they should be reading tutorials about arrays, and searching for "use array in php mysql query", etc.
This is after all a Q&A style network of sites, and not hold you by the hand helping you build every step of your site - not saying this is you, at all, and as bad as blanket policies often are, they are also unfortunately sometimes the only viable option.
While you may not be that type of person, waiting 20 mins is not the end of the world, and don't forget it ensures the site stays clean and spam free for you to browse for good concise answers too. Nothing worse than a quick Google search to find a result seemingly perfect for you, to hit the link and be taken to a forum where the question and following answers are rubbish and someone link spamming their own site, or whatever.
(Yes I said there that Stack is making the internet a better place, but having raked through forums in my time for answers, it actually IS true)
So to resolve it, I suggest doing your questions one at a time. Search here/Google/etc for answers to your question 1, if nothing found, construct the question well with code etc, and post it.
Then start searching on Stack/Google for help with your second question. By the time you've researched question 2, and tried a few things, and read and discussed all comments and answers on your 1st question, and tried a few things from that, you'll probably find well over 20 mins have passed by.
You might even get an answer from question 1 in this time, and so have some more coding to do.
If you have more than 2 questions you need to ask right now, it's likely (note "likely") you need to be reading a tutorial or learning and researching some first. Not always, granted, but again the blanket policy is there to stop the masses who would abuse it.
The summary is simply work around it. Do what you can with the tools you have. I know you may be just doing one script and are sat waiting for the answer, ie cannot start another project or phase of your current one. However, there must be something you can do for 20 mins?
Use the time you're waiting to take a break, re-evaluate your other code or what you've coded today. Bug check, check that error log to make sure there are no warnings that you don't know about. Test some other code just one more time, plan your next stage. etc
Removing the limit and making people review, as you proposed, is no resolve, as all the crappy/spammy questions will still come flooding in just as if you had no review stage and allowed questions (my points above). So then it has to be thinned out and just creates a load of work for numerous people, more work than the good it does. Especially as the main argument is that there is no real need to post more than one question every 20 mins.
It's possible that a particular person might be able to post two good questions less than 20 minutes apart. For all I know, you may be that one.
But that's pretty rare. MOST people that post questions so close together will have a problem of one sort or another, either because they are spammers, or because they're not "good enough" to post good questions so close together. The site policy addresses this large majority.
Having such questions go through a queue would just clog up the site. The easiest solution for everyone concerned is to ask that "rare bird" to wait a few extra minutes, probably no more than five, certainly no more than 20, before posting a second question.