All airports suffer from queues at immigration and it is the airport which always gets the blame. Immigration is operated by HM Customs & Excise who are a law on to themselves. The airports have no control over the operation at all.
Having said, that I went through immigration at Liverpool within 5 minutes the other night. I totally disagree with Spandau's comments. I travel through Liverpool three or four time a month and I have always found it to be a pleasant airport to fly through. Liverpool is no more "bucket and spade" than Manchester for instance.