The Bonaventure as seen in TAS makes no sense because it's just so obviously a play on the familiar E design. But in designing a live-action version I still wanted to try evoking elements of the TAS ship. But maybe it's best just to start with a clean sheet.
Well, we only see the Bonaventure from one angle in TAS. My own approach to this was to try to match up the TAS "view" with something that's still quite a bit different from the TOS Enterprise, and clearly a lot more crude (someplace where ENTERPRISE failed, I think... they tried to make an "older ship" that was simulataneously "more advanced" than the TOS ship.)
Scotty's reference that the Bonaventure was the first ship with warp drive has to be interpreted. When Cochrane introduces his space warp tech it could be that folks were strapping it onto all sorts of things in a hurry to get going. Maybe what Scotty really meant was that other than Cochrane's prototype the Bonaventure was the first ship to have been designed from conception with warp drive. In that way it makes even less sense that the ship would look like what we saw in TAS. Then again I look at TAS as something of an animated storyboard of live-action events from the TOS universe.
Well, this is, to me, yet another bit of corroborating evidence that "warp drive" and "faster-than-light-propulsion" aren't synonymous... that "warp drive" is just one possible FTL propulsion system, and is fairly recently developed (in TOS terms).
This goes along with the "more technical" description of warp drive used under Pike's command, and with Jose Tyler's comment about there having been a propulsion-system breakthrough, and with the concept that the Romulan war was fought with ships using "simple impulse," and on and on.
It's really pretty clear to me that "warp drive" was developed a few decades prior to the Enterprise (under Pike) arriving at Talos.
If that's the case, it makes a lot more sense for the Bonaventure to have been the first ship with that particular form of FTL propulsion. Doesn't mean it's the first FTL ship.
Either way, though, we have to "retcon" "ENTERPRISE" a little bit. In my case, I can watch it just fine, and simply refer to what they call "warp drive" as "FTL drive." In your case.... I'm not sure.
(-: The more I think about it I feel that I'm not really that far off in my general idea for the Bonaventure, but that it shouldn't be much bigger than the Valiant either.
The Bonaventure shouldn't have had a big crew, but should have had some self-sufficiency that other ships (perhaps like the Valiant) wouldn't have had.
Remember, the ships in the "Delta Triangle" had been stranded there for decades, yet they weren't all starving to death (yet). Obviously, they'd have had to convert some portions of their ships to hydroponics and so forth... but for a ship like Bonaventure to have been a practical "long-term habitat" you'd have to accept that she had to have a lot of space for that sort of thing.
Of course, the Bonaventure ought to be smaller than the 1701, I think.
Not wanting to "hijack" the thread, but here's are a couple of images:
First, the Bonaventure as seen on-screen in TAS:
And my version of the Bonaventure, from effectively the same angle:
But it's not the same as the Enterprise, and is quite a bit more "crude"...
There have been plenty of other "takes" on the Bonaventure, some trying very hard to replicate the ship as seen on-screen (which really doesn't work very well, I think we'd all have to agree), and others trying a pure "clean-sheet" approach.
The Sternbach/Okuda take:
The "Ships of the Line Calendar" take:
I think that the trick is to try to capture the general appearance seen on-screen while still doing what you're trying to do (that is, making it distinct and less-advanced).