Recommendatios?

Class D has improved quite a bit over the last 10 years. Consider a newer integrated in either Class D or linear ranges.

I'd ask about bass traps, and room modes.

It could be you need not anything better, just different. 
I don't know of speakers I like better than Wilson's. There are lots which will give you more "detail" or have a different bass/mid/treble balance.

B&W, Golden Ear (shiver), Dali are speakers that fall into this category.

Monitor Audio, Revel are pretty neutral as well.

You might want to go out and listen between them.

ESL's can be wonderful for their imaging, but lack in dynamic range and overall tonal balance.

As far as the room, have you added any diffusors, or are they all absorbers? They can add a sense of liveliness and balance.

Appreciate responses and suggestions, will take all under advisement.  Duke envisions correctly that speakers located at end of one long wall facing opposite long wall and only several feet from the side wall so there is a lot of asymmetry regarding speaker placement.  I believe I get decent imaging and sound stage  but not a lot to compare it to.  Could reorient speakers to face the length of the room but would block windows with nice view.   I do feel like there is a feeblenesss to the sound which may be related to room size and speaker placement.  Have only absorbers and no diffusers.  Did add an old 100 watt Velodyne 10 in. Sub parallel wired to speakers and that did make a very noticeable difference at the low end.  Maybe I just need more juice in the amp/speaker combo.

Isnt the Dsi200 a class D (switching) integrated amp? The only time I could stand to listen to the older Wilson was with tubes. If you have one of the older Wilson tweeters I wish you luck with the high end. My initial thought is to spend more time on the room acoustics and then get rid of your integrated amp if things havent improved to your satisfaction. Once again I preach the gospel of getting the room right before doing anything else.   

You are correct.  The 200Dsi is a class D with 200 watts at 8 ohms and 300 at 4 ohms which I have assumed is enough juice.   You are also correct that high end sounds a little anemic.  Will take your advice and get some local expert input on getting the room right before moving on.  If that doesn't do it, do you have speaker/amp Recommendations? Thanks

There are a number of good sources for acoustic information. "The Master Handbook of Acoustics" is a great book, but much of the information isnt applicable to the 2 channel room. 

I have found GIK Acoustics to offer good advice and they have some reasonably priced products. Do some research and talk to a few companies that sell products of this type. Also check out some of the free information and services offered on these sites. Much of these products you can make yourself if you are of a mind. 

So much to cover and so many things that can be done to a room for pennies when you compare these costs to that of equipment. My advice is to decide which are your highest priorities with your system (dynamics, organic quality, detail, etc) and then post here again. If you can isolate your single highest priority this would be great.

I have a problem with people blindly providing names of products, and I have done this myself, without asking the proper questions. I would avoid professional reviews, hold owner reviews in a bit higher standing and listen as much as possible to different systems. If you can, go to any of the various shows just to get a feel for what type of sound you like. 

I think that Ralph at Atma-sphere gives good advice as does Duke at Audio Kinesis. I am sure there are many others. The people that dont give you quick answers and ask additional questions are often the ones to listen to the most.