Ignore queue limits if speed is less than

Basing on the speed would probably affect performance since you need to keep checking the transfer speed of active torrents and toggle their torrent_handle::auto_managed() state.

I believe a middle ground here would be to not count in the queueing limits torrents that are not transferring anything. This is more efficient because supported by libtorrent:
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if dont_count_slow_torrents is true, torrents without any payload transfers are not subject to the active_seeds and active_downloads limits. This is intended to make it more likely to utilize all available bandwidth, and avoid having torrents that don't transfer anything block the active slots.
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I can add support for this in next major release if you are still interested.

Yes this is an acceptable solution for the time being.
I had a look in the libtorrent API and I came to this conclusion. If we want to have more advanced queue logic/options then we must manage the torrents ourselves. This requires a rewrite of the code and thus will remain in the "wishlist". And I think this is the only way to implement a "force" torrent option.

Implemented in v2.9.0.