To begin there are a number of things about L4 I do like but a real problem with it for me is how searches are done and returned.
I do a significant number of topic based searches and a pre L4 example of that was a class I did on angels. L3 would return topic searches in a format which is much more useful than the 12,279 results in 2,380 articles listed across 24 sceens or pages of output. I'd liken it to doing a Google search where you end up scrolling through page after page of results looking for something on target.
I thought perhaps searches would suport tagged searches such as topic: angels or subject: angels but no, that only added topic and search to the searched terms.
This would be partly aliviated if under book if would just list the source and number of articles under it to compact the results. Yes I could set up collections but then I loose the point of a very fast search engine and would miss those resources that might be relevant but which I didn't think to include in my search. But even more useful would be a true topic based search rather than a shotgun all instances search, which to me is nearly useless. As it is I'm doing my serious work back on L3 and just playing with L4 which makes me glad I didn't upgrade a level or two because the L4 just isn't ready for prime time.
A couple of other things that are problematic. I have L4 installed on my office machine and a lap top. The sync idea is very good particularly for collections and upgrades but automatically setting the displays across isn't. I use the two computers differently and I'd like the abuility to keep software sync'd but leave my screens alone.
I also do a fair bit of work in original languages. I really do not like the way interlinears are displayed, preferably I should be able to use them as they were published and at the very least they should scroll with the text.
I also think the menu has been overly simplified. I appreciate the ability to directly call up certain features. Yes that does require a bit of a learning curve for new users but for the huge installed base, if they are like me, the current menu is a real problem. It reminds me of MS Word upgrade where I spent 90% of my time looking for features I needed ubntil a decided just to can MS office and went with open office instead.
As I said, some things on L4 are brillantly executed but I think a lot of it was never taken beyond the "gee whiz" look how cool this is stage into what the functions were being used for and whether it served a functional purpose.
Hope these issues are addressed sooner rather than later because L4 has real potential.