Anyone Successfully Go from Floor Standers to Bookshelf Monitors w/ Subs?


My system is in a Large Living room which opens to dining room & Kitchen. I figure about 6k cu ft. I have Silverline Sonata speakers now with subs. Unfortunately I did not build my addition when I should have 10-15 yrs ago. Now I'm not really up to the task. Too old & wore out. So I'd love to make the LR a prettier room for my wife. One thing we talked about was the large speakers, and possibly using Watkins Gen 4 monitors. But as good as they sound, I am concerned about the ability to fill the room, or at least my listening area. As I understand, it is about moving air. I cannot see how a 6.5 & 1 inch speaker can move as much as a 10, 7, 3 & 1 inch. So I am quite concerned about that. Right now, the system sounds very pleasing to both of us. We don't want to take a backward step but can live with a sideways step if it is more visually pleasing.

Has anyone made this kind of a step from floor standers to monitors, both with subs, in a large room, with success? Or am I thinking correctly about the small speakers inability to move the proper amount of air for the room size? Thanks for your help.

OH, FWIW, The addition may not be completely out of the picture. But it depends on whether I can get one of my previous sub contractors to do a large part of it. 
128x128artemus_5
When I moved some years ago, I ended up with a smaller listening space. Found that my Vandersteen 2CEs just didn't work well in close quarters. They need room to breathe and that's something I didn't have. Ended up replacing them with Kef LS50s and a Rel T/5i sub. The LS50 coincident/coaxial driver design works very well in nearfield listening situations.   
There are many floor standing speakers that are quite thin and uses 8 + 6 inch drivers or many 8 inch drivers. One of those with a sub may be a good compromise. Could look good and fill enough of the room.

You can also listen to the Kii Three which moves a lot more air than you would think. But that would replace your amps as well.
Slightly off topic: Do you remember the double large Advent speaker setup? I have often wondered if that kind of synergy occurs with other monitor type speakers. Anyone here ever try that with today's high quality monitors (Watkins, Fritz, ProAc, Harbeth, etc)?
Wow! So many responses to answer. Thanks guys. FWIW, the Watkins Gen 4 have a return policy and Watkins Stereo is about 3 miles from my house. So, they wouldn’t be that hard to return. Once again, I have 2 Rel S5 subs (with Sumiko S-10 badges) So the subs are adequate for the job and I like them. I agree with @rauliruegas about the setup and crossover points. I have also played live music (drums & vocals) so I KNOW what a bass guitar should sound like and these subs do that well.

@allenf1963 We may be neighbors. I’ve lived in Kingsport for 25 yrs and have known Bill Watkins & his son for 35-40 yrs. I used to go up to just talk with Sr from time to time prior to his death. Bill Jr, says he was a genius and I believe it. I know about his patents & I believe he holds some on the Gen 4 too. Both speaker drivers are modified by Bill to get the desired outcome. He told me before he produced them that he was working on the best speaker he had ever produced. Again, Bill Jr says they are better than the WE-1’s. There again, Jr’s hearing is not as good as his fathers from what I understand (tinnitus) Nonetheless, both of them are very knowledgeable and are men of high integrity, IMO