Now that we have smarter multi-term queries, I think its time to reconsider the boolean max clause setting. It made more sense before, because you could hit it more unaware when the multi-term queries got huge - now its more likely that if it happens its because a user built the boolean themselves. And no duh thousands more boolean clauses means slower perf and more resources needed. We don't throw an exception when you try to use a ton of resources in a thousand other ways.
The current setting also suffers from the static hell argument - especially when you consider something like Solr's multicore feature - you can have different settings for this in different cores, and the last one is going to win. Its ugly. Yes, that could be addressed better in Solr as well - but I still think it should be less ugly in Lucene as well.
I'd like to consider either doing away with it, or raising it by quite a bit at the least. Or an alternative better solution. Right now, it aint so great.