Interesting post regarding BizTalk and/or other integration tools as overkill for some integration solutions.
I've had similar experiences with BizTalk and it is likely the same with other 'Enterprise' integration tools. In other words, KISS and YAGNI.
BizTalk Light to me is the ability to code/deploy to the orchestration, adapter, rules and BAM capabilities from within my application code. Sometimes I need a dedicated, scalable and centralized solution. Most of the time, I just need a handy and simple integration framework to code against.