Can you be more specific? I don't mind the accusation, but peope on the internet™ have often different expectations of what a software should or should not do. There is no such thing as the perfect product™. It is all about tradeoffs.
A host can also be a subdomain. I'm using Isso on my personal blog for reference: https://blog.posativ.org/. It works exact the same way as for a top-level domain.
You are not doing full-text search with bloom filters (unless you add all partial words to the filter), only word-search, which is imho the biggest disadvantage (e.g. typos in the index or on the client's side).