Antares, Deadalus, Woden, Aurora, Class J, Denevan, Medusan, SS AStral Queen, Kobayashi Maru, Constellation, Miranda, Oberth,Soyuz, Merchantman, Whorfin, T'Pau, Vulcan Warp shuttle are all the TOS or TOS-moves era Federation ships we have seen (that are listed here). All of them are either confirmed or very much indicated to be smaller than the Connies.
Wow that's a doozy of hilarious error...
1) Daedalus was from a century earlier than the Enterprise and its actual size was never given. It has never appeared on screen (we don't even know, canonically, what it looks like)
2) Antares' size was never given, nor was it ever compared to the Enterprise. It has never appeared on screen.
3) Class J's size was never given, nor was it ever compared to the Enterprise (it was only ever described as "old"). It has never appeared on screen.
4) The Denevan ship was described as a "small one man craft" and was not a Starfleet vessel. It has never appeared on screen.
5) SS Astral Queen was never compared to the Enterprise and has never appeared on screen.
6) Constellation is the same class and same size as the Enterprise
7) The Miranda class is 10% LARGER than the TOS Enterprise
8) The Merchantman is not a Starfleet vessel (we're not even sure it's a FEDERATION vessel)
9) The T'Pau is not a Starfleet vessel and was never directly compared to the Enterprise.
10) The Vulcan Warp Shuttle... is a shuttle

11) Whorfin is never compared to the TOS Enterprise and we don't actually know how large it is in the first place.
Summary: The vast majority of these ships are not Starfleet vessels and very few of them were ever confirmed or even implied to be larger or smaller than the TOS Enterprise.
Your'r willfully obtuse, again. In EACH ERA, the Enterprise OF EACH ERA is always the most powerfull, biggest ship.
And all you have to do is find a SINGLE line of dialog where anyone states that the Enterprise, Enterprise-A, or even Enterprise-B is the most powerful OR largest ship in any fleet it belongs to. Just ONE line of dialog, in 79 TV episodes and 6 major motion pictures.
Start here:
http://www.chakoteya.net/StarTrek/index.html
If this is indeed true EVERY. SINGLE. TIME. The series should be full of such references, yes? All you have to do is give me ONE.
The only ship bigger then the Ent-A was the Excelsior - and the Ent-A was pretty fast decomissioned after the Excelsior entered service...
Seven years later. Which again makes your statement factually incorrect; if the plan had been for the Enterprise to be the largest ship in the fleet (and there is even less evidence that this is true of the Excelsior) then the Enterprise-A would have been an Excelsior class starship, not another Connie.
EVERY. SINGLE. TIME. The Enterprise was on-screen, it was the biggest and most powerful starfleet/Federation ship around.
Except for all those times it was exactly the SAME size as the other Federation ships around, right?