so....When I was a kid the only people who bought dyna's were 1%'er and people who wanted to embrace that aspect of the HD lifestyle. The people who wanted "retro" bikes bought softails or sportsters. I have to say I am not sad in the least about the dyna leaving mostly because it was probably the most stoneage platform the motor company had. from 1971 to 1992 the FX (predecessor to the dyna) was basically a parts bin special using the frame and engine of the 1965 FL ElectraGlide and the front parts of an XL sportster. In 1991 they redesigned the FX line into the Dyna chassis but kept that old 1965 rear suspension setup and even deleted some of the rubber mounting (WTF). The Softail may be technically older having been designed in 1984 than the dyna chassis, but it wasn't a parts bin design - it was clean sheet and it has enjoyed a lot of updates over the years. Sportsters usually take crap for being the HD that goes multiple decades without a significant chassis re-design, but even they had more interesting derivative models like the buell line, xr1200, etc....
I don't think HD is giving anything up by killing the dyna - the bike was a relic and it was the wrong kind of relic. It had turned into the cheap floor model compromise people who couldn't afford a softail but who shat on sportsters as "Chick bikes". It was "retro" only because it had aged into being retro - it wasn't designed to evoke anything from the past like the heritage softail. The only saving graces it had was for a while it was the big twin least affected by bloat because it was a parts bin special, carried a high profit margin because it was a parts bin special, and got people into big twins who otherwise couldn't afford an HD because their macho ego wouldn't let them even consider a sportster.
The new bike chassis is far and away better than anything the dyna aspired to be. The same familiar models like the low rider and street bob are still going to be there, and still at the same price point, but now they get a monoshock setup that looks like HD robbed the TZ750 parts bin. They get more turning clearance, more accessibility to performance parts, aren't spooky handling anymore, and guess what - HD gets to decrease it's mfg cost by having only once chassis for the big twins so it's profitability margin goes up on all big twin bikes, instead of being centered around the dyna.
Personally, I own an ironhead because if I wanted a retro 1950's bike I might as well own something that actually was designed in the 1950's and feels exactly like it because it didn't change from 1955 to 1978, and that is the cheapest way to do it. Dad owns a 1997 fat boy because he really loved the look of the fat boy and bought one new...oh and also it's way easier to reliably supercharge an EVO fat boy than any earlier HD model. The same people who bought Dyna's before will continue to buy dynas because "sportsters are for chicks", but the only thing that will change is they will actually get a lot more motorcycle technology for the money.
How could it be a bad thing?