Bookshelf Speakers that have to be up against the wall

just to add that my Proac Tab 10's on cabinet are in a mid sized bedroom, not the main system. I wouldn't recommend tablettes for a large room necessarily. good luck.

In my home office's desktop audio system, I've had 4-5 pairs of speakers over the past 12-13 years (2 powered; 3 passive). All were located w/in ~1 foot of the front wall (actually an inset picture window covered with heavy blinds). 

The main thing I learned is that sealed/acoustic suspension systems work better near a wall than any ported designs. 

I currently have 2 such speaker pairs: my main pair is ATC SCM12 Pros, large/heavy 2-ways that sound rather amazing. 2nd pair is a pretty 4-yr old pair of Aerial Acoustic 5Bs, also a relatively heavy 2-way system. The 5Bs have better soundstaging and would probably light up the room w/soundstage if pulled out from the wall & put on stands. I'll sell the 5Bs soon because I just can't keep multiple pairs of speakers going...and I love those ATCs. 

Had the Wharfedale Diamond 225s here and they sounded pretty good, though clearly not in the league of the 5Bs or ATCs.

Sealed is the way to go when near-wall placement is unavoidable.

Note: my system is nearfield, which probably minimizes the soundstaging deficits of close placement.

++ Linn Sara (if you find any they may need a little attention but you won't hear better! ).

You lost your imaging the minute you put the speakers right up against the wall. Only thing worse you could do is put them on an actual bookshelf with books and stuff lined up flush with the front of the speakers.

Books can actually disperse the reflection and act beneficial

This is because all speakers, in order to sound their best, need to be set up so the sound goes from the speaker to your ears. What you have now is the sound goes from the speaker to the wall to your ears. Every sound coming off the speaker reflects within a millisecond off the wall, and not just the once either but constantly across the whole surface of the wall, until the sound reaching your ears is this garbled mess, which is why they image so poorly now.

To which wall? By placing them theoretically flush with the wall, you actually remove reflection from back wall and you get an infinite baffle that can reinforce lower end. That way you could get by with compression box which will have better transient response and still get good bass extension. Then, there won't be any baffle step that needs to be taken care of in the crossover at the expense of loosing efficiency. 
If the wall is treated/covered with absorbing material I don't see any problem with imaging. Imaging is is defined by cues higher in frequency where the speakers are directional anyway.

There are speaker designs for wall mounting or against the wall and they can work pretty well.

Also put acoustic panels on the wall/surface behind the speakers.
Will help tame some of the bloat....