I don't think you realize the question volume of Stack Overflow. A 2nd active page would do nothing. With approximately 10,000 new questions per day, that comes out to an average of about 7 new questions per minute. Couple that with about 11,000 new "answers" per day (rough estimate based on the new answers, assuming a large number of deletions) and a virtually limitless number of edits that bump posts, a second active page would keep a post on the first active pages for just a few extra minutes.
This is why Stack Overflow's front page is not an "active" page. Instead, it is replaced by the "Interesting" page, which customized for you based on your preferences and habits on the site.
You can find the details in Stack Overflow Homepage Changes
Here’s how it works. Starting with a list of the last 3,000 active
drop questions containing any of your ignored tags
drop closed questions if you lack the reputation required to vote for reopening
drop questions scoring -4 or lower
Next, apply the following score formula to the remaining questions:
your interesting tags
+1,500 per interesting tag, up to +2,000 total
your top 40 scoring tags maximum of
+1,000 per tag (scaled), up to +2,000 total
+200 × score, up to +1,000 total
total answer score
-200 × score, up to -1,000 total
number of answers
-200 × answers, up to -1,000 total
number of views
-15 × views, up to -1,000 total
question last activity date -1 ×
(seconds / 15)
Count it all up and take the top 90 by score.
The idea behind it is to present interesting questions to potential answerers, not give the more crap to read.
This is all being replaced with a new "recommended" tab, but that algorithm that populates it is still a work in progress. You can read more about it in Feedback requested: New "recommended" homepage, phase 3 - algorithm tweaks
Question quality plays a major role on Stack Overflow, so it is important to highlight the good questions to help separate them from the garbage. Questions that are not of good quality are quickly buried.
At the same time, the breadth of Stack Overflow's scope also results in a lot of active questions that are not important to me because I have no interest in the particular language, so it is important to also suppress those questions. Why waste valuable screen space on sometimes I don't care about.
and even this is not good enough at times, which is why Stack Exchange is working on a new recommended front page. You can read the details in Feedback requested: New "recommended" homepage, phase 3 - algorithm tweaks
If you have specific concerns about it, you can express concerns about that algoeithm there. Now if the Math is starting to move too quickly, on its Meta site, you can suggest they move to a different version of the front page as well to help highlight good questions that are interesting to you and people who would be able to answer your questions.