I think Attila's enthusiasm for improving slime is great, however, I also think that some of the unspoken rules of open source have been broken here.
These conventions are documented in ESR's 'Homesteading the Nooshere', but since that essay is rather long winded and philosophical I'll summarize here.
1. Attila, you're playing on Helmut's turf, you need to respect the ground rules set and also accept that Helmut has final say.
2. If you really, really can't abide by point 1 then you should create a proper fork. This means choosing a new name and creating a new project with its own mailing list. On your project website you should also try and justify the fork and the inevitable drain on developer resources.
Note that forking due to trivialities is highly unlikely to attract other developers.
Once you've forked, it's inappropriate to send suggestions to the slime mailing list. If you wish for slime to continue to improve, then release your fork under an open source license, but allow slime developers to port the changes they want. It's especially bad form to re-suggest changes you couldn't push through before the fork.
http://article.gmane.org/gmane.lisp.slime.devel/5542 http://article.gmane.org/gmane.lisp.slime.devel/5788 http://article.gmane.org/gmane.lisp.slime.devel/5953
So I think Helmut's position is justified and not an overreaction (although an ultimatum is probably not the most effective course of action). My advice to Attila would be firstly to apologize, then either retract the fork or commit to it, the current situation cannot continue.
just my 2c