Currently, if someone has a net 0 number of inclusions (with at least one inclusion), they will be in your trust network, and the only way around this is to manually exclude them.
No, that's not how it works. No amount of inclusions or exclusions affect my trust network. Only my inclusions and exclusions have any effect. If I have my trust system depth set to 1 or (the default) 2, then those who are included by the members I've included will have an effect. Again, you're missing the point; this proposal has nothing to do with inclusions and exclusions on their own. It's about those 100 or so members who are on DT1, and the affect their inclusions have on the system as a whole.
There is one thing you are leaving out -- the underlying reason why someone has this power is that many people have included the person in their trust list. Those who are on DT1 is (somewhat) random, and does rotate, however the people who are on DT1 are not arbitrary, they have effectively been chosen by the community to have this power.
Indeed, they have been chosen by
a very small minority of the community:
A little over 5,000 users have voted, and those votes affect the forum's trust system for millions of users. Not my idea of good representation. Doubling the threshold for DT2 inclusion isn't going to fix all the abuses from which the trust system suffers, but it'll make it a bit harder to abuse.
Do you think there is any chance that theymos will implement a change in this regard?
This is a very good question. History tells us that there are very little chance for him to do something about it. He must have other priorities 😉
I disagree. Let's be real, this is theymos' forum and he may disagree with the premise of this thread. What he chooses to do is purely up to him, but he's been accommodating in the past. Not long ago I made a stink about all the AWS scammers in the digital goods section, and he responded by banning those sales:
https://bitcointalk.org/index.php?topic=5173486.msg52093309#msg52093309