Transfering from Proxomitron, I really miss one useful feature for filters - numeric range matching. Proxomitron implementation [#n:n] for positive integers was extremely simple and sufficient. Please see http://www.proxomitron.info/45/help/Matching%20Rules.html
Since pcre doesn't contain any similar feature and RFC 197 (http://dev.perl.org/perl6/rfc/197.html) isn't probably implemented, I'd suggest to introduce some similar specific numerical range matching rule, which might be in the case of presence rewritten into regexp by rules written for example here:
It would help me much! Thank You.