I will reply to your post:
1. The commentators are useless, in this game sounds meanwhile jumping are enough. But, it's really boring that there are the same sounds on every hill. Every onefold hill should have his own, unique sounds, especially on inrun, because inrun tracks on every hill aren't the same, not counting hills from hill groups.
2. Yes, dead jumpers after falls are irritating, but it seems to be one of signs of DSJ. xD
3. Interface of this game is really obsolete. That's one of some things that discourage potential buyers.
And now my opinion:
The game is less simulator than it is written on site. Physics are not as real as in real ski jumping: why there is gibbon? And how it's possible to jump long with flight style similar to Stefan Hula, if we look on 'stoop' of jumper in flight? More successful should be flight similar to Peter Prevc, it will be great on every type of hill. And why we can land with telemark on incredible lengths (BM- 220, Engelberg- 142.5, Ga-Pa- 147, Harrachov- 216-217, Kuusamo- 152, Lahti- 139, Lille138- 149, Oberstdorf- 227.5, PC134- 137.5, Planica- 239, Sapporo- 145, VdF106- 109.5, VdF134- 138.5, Villach- 103.5, Wisła- 139, Zako94- 97.5)? Hill records should be similar to them did in World Cup or on some hills a bit better (max. 1 meter, but not 5 as in Lahti, 7 in Sapporo or 8 meters in Bad Mitterndorf!) Also, hills aren't ideally mapped from real world, there are a lot of details to change: banks, startgate steps on inrun, and mostly environment of hill.
And this disastrous system of finding a wind... There should be system, which says that for onefold startgate should be assigned specified wind interval, and maximal difference of strongest and weakest wind should be dependent of number of gates available in World Cup mode. It will be more simple and will eliminate most of fortuity in finding wind. And reducing maximal wind from 2.5 m/s to 2.0 m/s and made it stronger feeling than 2.5 m/s in DSJ4 - it will increase again the reality of flight. And inrun speeds difference - it should be maximally 0.1 km/h in the same wind, but not over 0.5 km/h, as it is now in DSJ4...
Also, the CPU players are too easy. Maximal level of them should be in my opinion 1800. More normal might be 1700, but I think 1800 sounds better.
All World Cup hills from last a few years with other hills from hill groups are enough. We don't need hills which are rarely used or they are out of order (Zakopane HS94), and, of course, not rebuilt hills (Bad Mitterndorf, Planica).
Also, why we have Team Cup mode and we create teams, if we could assign jumpers created in World Cup mode to teams and play Team Cup in World Cup mode? It could take less space, I think.
Anyway, the interface of site and forum is even more obsolete than interface of game (main menu).
And, of course, too high price to offered capabilities. Maybe 1-year subscirption to online game instead of 3-month just after buying the game couldn't be more tempting for potential buyers? And of course, the brutto price may be the same as actual netto price. That's why a lot of players don't want to buy the key. And now you see why a lot of players don't want to buy online subscription. The game is simply too boring and underdone.
Yes, it's better to say latest version "Beta" than "FV".
There are compatbility issues to fix, but it's a lot of them and the most of them are large or medium.
...and now I am waiting for any player who will call this game "professional"...
. All I know , is that writing about me, "hacker", I'm proud of myself for what I achieved in DSJ 4. Do you have any idea about the game, it does not offend other players. I know each other from Maciek reached in this game is what I can dream .... 
only just for a respect for Mediamond as a company , and FAITHFUL players