always amazing what keeps some people awake at night dreaming about "that would be so cool". 
the op thinks a "low and slow free kill hangar queen" like a zepplin would be cool yet his stats shows he doesn't like being caught in the existing low and slow...
There is an axiom that is generally held to be true in the AH community and that is: If you don't like it. Don't fly it. There are many Aircraft that dubbed "Hangar Queens" and see little to next to no use in any arena; but that's not the point here. The point is two fold: Suggesting a beneficial Aircraft and suggest one that is potentially game enhancing not just to one specific arena, but rather multiple Arenas. The Blimp was a successful Convoy Escort, Observation Post, and historically the first Strategic -internationally capable- bomber. The aircraft, in this case lighter than air, made contributions to both wars in it's own unique way- and is currently being researched by the DoD and DARPA to fullfill the same roles in a modern context (which includes providing realtime battlefield Recon, C2 and,C3i).
Yes the Airship is slow. Very slow by piston fighter and jet age standards and highly susceptible to ADA weapon systems, but it can be argued that every wepon systems has trade off's in advantages and disadvantages. I've listed some of the benefits of having Airships in game, especially in the World War I Arena- where I state again- The airship found the most use as a front line combat aircraft (despite that Arena seeing little use.)
By comparison the P-39 "Aircobra" was, by most historical accounts of it, an abysmal performer- yet it's in the game. The Russians managed to use them to some measure of success agianst German Armor and in some cases Aircraft such as the Me-109(Bf109). It even sees some use in Game. Another Comparison is the Fi156. It's low and slow, and its used.
Frankly, The Airship has a record of use and success (far longer than any piston engine or jet fighter) dating back as far as the American Civil War. What other Aircraft can claim that? What other Aircraft can claim Longer flight duration times, Lioter times, and Energy conservation ( in terms of fuel spent and manning requirements)? None.
This aircraft has the potential to increase the historical aspect of the entire game- not just one historical segement of time. Yes it's slow and highly susceptible to enemy fire- but it has made significant contributions to in spite of these limitations. Most Aircraft are built to fulfill a doctrinal niche or to apply a particular aspect of Air power Theory. Very few have actually proved the feasibility and was adapted to fulfill that role. Airships were the original Multi-role Aircraft and have evolved just as the Jet or piston engined plane has.
