Out of curiosity, is this thread discussing maximum theoretical fleet strength after a grinding endgame Ordos, or is this about usage on the way there?
The idea behind Support Doctrine is to enable a different playstyle. As pointed out by the OP you can cover 240 DP worth of ship in officers without much effort. But what happens when we start from the assumption the player is running 25 Combat ships and 5 logistics ships as the style? I mean, we can say you shouldn't do that, because of officers. But does Support doctrine boost such a fleet to making it sufficiently viable for end game play? Having a really wide frigate/destroyer swarm is certainly a different experience than an officer limited capital/cruiser/frigate setup.
On the other hand, I would expect Support Doctrine to be terrible on an 8 ship only fleet, because in some sense it's a highly specialized skill, while Best of the Best is the generic, useful in most fleets choice.
Since we're discussing a wide fleet with something well over 10 combat ships (since you have more ships than officers/player), and likely pushing more like 20-25, Best of the Best's third s-mod is not free. You're talking about 60-75 story points just on the ships, and likely another 10-20 on officers, plus another 5 on personal skills. 85-100 story points is a non-trivial amount of grinding, and a fair bit of time where it's not 240 DP worth of an extra s-mod. Peak power is likely higher, but I wouldn't say it can be assumed or that it's the default. Do most players grind an additional 40-50 story points past level 15? And is that the balance point we're discussing (having used of order 100 story points), or the power balance on the way to having earned that many story points,at which point not all 240 DP has triple s-mods during the grind up.
The other half of Best of the Best gets you 200 DP off to start, but getting to 240 DP takes exactly the same amount of effort as for a fleet without. Since it doesn't stack with capturables, but counts as if you had a minimum of +40 DP (assuming a 400 DP setting). If we're discussing absolute peak fleet power, which requires deployments of 240 DP, Best of the Best doesn't really matter too much for that. Assuming you've got fast frigates, capturing 80 DP of satellites each fight is pretty trivial at the beginning of every fight (2 Hyperions or Afflictors can grab at least one of the far one's on an even quad spread no problem).
As for comparing the differences between officered and unofficered ships. It is probably a comparison between a level 5 officer with an elite skill versus level 3 officer and +25% more ship. I'd argue +25% more ship is worth at least 2 officer levels. Field modulation is -15% damage (17% more shield tanking) and Target Analysis is +10-20% damage. +25% more ship nominally should mean you can absorb 25% more damage and deal 25% more damage from that DP investment from a fleet perspective. It can theoretically be a larger multiplier than that since the AI starts having problems when in 2 vs 1 situations. If you effectively have a bunch of 1 on 1s, but there's a 1 on 2 at the very end of the line, that can have a snowball effect on close fights, at least it does in PVP tournaments. Almost all fleets in those types of situations go wide. Number of ships on the field matters to the AI.
Edit: Actually, it can be more than +25% more ship, as Lasher's drop from 4 DP to 3 DP, for example (+33%). Enforcers drop from 9 to 7 (+28.5%).
While I agree, at peak power, Best of the Best and staying within your officers limits is probably stronger, that isn't a 20-25 combat ship fleet. I think support doctrine isn't that far behind for the fleets which it is designed to enable. It is certainly far cheaper in terms of player time because of the s-mod costs associated with Best of the Best. At level 5, the first point at which you could take it, assuming you're just salvaging ships as fast as you can, to get as wide a fleet as you can, it should be a much, much larger boost than Best of the Best. Especially with only 16 story points in hand. If you have ships you don't plan on keeping long term, Best of the Best does nothing for those ships, or else it significantly increases your long term grinding goals as you'll need to replace 3 story points for each ship you've discarded.