I'm Max from Italy, and I'm new to the forum.
I have several CM's cases, and 690 adv II was my first love!
I still have it,and I hope to replace it with a worthy successor (which to my opinion the 690 III is not)
so I'm here to give my advice about what the 690 adv IV should have to be an absolute best buy (also seen the one offering the fierce competition!)
well, here is my suggestion:
1- create 3 versions: mid tower, full tower & mATX (like Silencio series): changes are only the number of front bay (height), but width & depth, and internal / external features remain the same...this in order to satisfy most users as possible !!
2- keep the bay 5.25 ", and the bay 3.5" : the tendency is to resize the number of the bay, but many users do not share "strange" placements of the ssd scattered in the most improbable & unsightly places inside!
I am convinced that -for example in 690 adv IV Midtower version- you can also increase the numbers of bay 3.5 "HDD approaching better themselves!
also reduce number of 5.25" bays or remove all direclty, it is a big mistake that many manufacturers competitors are doing, and the comments on the forums are ruthless!
the bottom HDD cage should accommodate 4 discs, because it is the ideal minimum number (equal) to conduct a raid with the hdd !! (for example with the bottom 3hdd cage into 690 advIII you can not !!!)
and then - Always in Midtower version- leave 4 bay 5.25", and under leave 2 120mm fans (in front of 8/10 bay 3.5") can be realized !!
in mATX version will be enough to put one 140mm front fan (4/5 bay 3.5") + 3 bay 5.25"
in successfull modern Case today are now indispensable:
- hot swap on front or top (like 690 advII or silencio series)
- card reader (like silencio series)
- multi fan hub on the back of the mobo (as Aerocool, Phanteks & Nzxt manufacturers)
- 2cm of backspace for cable management (as many competing manufacturers)
- cable clamp (as Phanteks Enthoo )
- rubber grommmets (like CM 690 II)
- predisposition for many fans (like CM 690 advII)
- easy remove of efficient anti-dust filter (tightly woven like silencio series)
- a vertical bracket that does bend the video card (as some lian-li manufacturers)
- plexy opening side window, with magnetic contact for the fan side (like Urban T81)
- hdd side opening mesh window (like Urban T81)
- hdd bay side front cover (like Phanteks Enthoo)
(the filters can not be super-fine, because an advanced user can move to buy DEMCiflex's magnetic filters set (which they surely would produce))
It could also be a full-featured version with:
- PSU covers cables less style (like Haf-x style)
- a front 4 fan Rheobus included
- 4 hot swap on the back of first 4 hdd 3.5 drive by bottom (like silverstone temjin T11)
- headphone side support (like TT Chaser A41)
about the fans nothing to say, because last silent CM's fans are excellent!
(but not use rear hdd fans like N300/N400: the arrangement of the holes of the fans would waste the separation of interior spaces! aesthetically ugly!!
something that would be very interesting is the unification of certain components (such as the HDD brackets x 3.5 ") for all series of your cases (for example, the supports for the ssd as already happens between adv690 & elite120) to optimize production and the store
in this context also an approach of design between 690 advII-IV & silencio series (and why not, with the elite mini series) would be interesting & profitable.
the aluminium plastic bar trim (on front & Top on CM 690 series) are your great ace in the hole that the competition does not have!
My big tip is: in the immediate future use well this ace even in elite, silencio & mini series and and why not, as a trademark in all other series !!
I hope my passionate advice can be read by someone important (after which I go to Alessandro Delfino and ask him a place in the CM Italy division!)
(and sorry for grammatical errors!)