Don't worry about those, everyone has their fav and least fav FC game—eg FC2 is my least fav, but it has a dedicated small core of fans who much prefer it to the others, I assume cos it's the FC game which veers most towards Survival.
Which FCs you like and dislike will likely depend on your own preferences. People who don't play the games, or just rush thru the story and call it done, talk about a FC 'formula'—whereas there are significant differences in many of them if you spend the time. The TLDR version:
♣ FC1—Phenomenal when it launched, quite difficult, some great missions, 2nd half a drag when Trigens appear. Brilliant at the time, only for nostalgia now.
♦ FC2—Worst of series, VERY annoying mechanics, tedious gameplay, repetitive, repetitive, repetitive … I never got beyond 5 hours in 3 attempts to play it without boredom & tedium becoming too much. Has a dedicated small core of fans who much prefer it to the others, maybe cos it's the FC game which veers most towards Survival.
♥ FC3—Really good gameplay at the time, enjoyable if you like over-the-top stuff, story missions mostly a drag, UI a disgrace. Comic book approach with caricature of one-dimensional villain—brilliantly portrayed by Michael Mando—and QTE events.
♠ FC3 Blood Dragon—way more over-the-top, not my cup of tea, but many like it as a short fun romp in 80s style.
♣ FC4—Excellent, improved FC3, much better story & characters, fabulous changing environment, less-worse UI, mostly good story missions, best gameplay. Nuanced political backdrop with most interesting villain—also great performance by Troy Baker—where the good guys aren't so good either.
♦ FC4 Valley of the Yetis—surprised me, well worth playing.
♥ FC4 Primal—Excellent, beautiful world of 12,000 years ago, great melee-heavy no-guns weapon play [beehive bombs!], not-too-bad UI, nice characters, base-building, ridiculously bad boss fights.
♠ FC5—Most variety in gameplay so far, lovely environment, interesting mechanics, fun story & characters, fun arcade mode; bad mission balance, unskippable tedious cut scenes, game-breaking timed run-n-gun sequences with major bugs—oh, I guess that should be spray-n-pray sequences, given the context. Resistance mod essential to avoid those problems.
♣ FC5 New Dawn—Very good, doesn't include FC5 game-breaker. Fun 'off-world' Expeditions which, like Outpost captures, can be repeated against tougher opposition for greater rewards. Didn't finish story, looks very boring run n gun stuff in YouTube, but rest makes it a great game. Worst villains of series.
Oh yeah, plot is always a fair criticism of a FC game. If it's story you want, and for some reason you've run out of books, then I recommend TV or movies—those are the story-telling mediums.
Games are about gameplay—all other aspects are welcome bonuses if good or somewhat irrelevant distractions if not—and FC series has that in spades…
IF you like the FC gameplay loops.
The maps are of course full, maybe those reviewers were looking for some particular content which wasn't there? I avoid transport as much as possible cos the maps are so interesting and rewarding to traverse and explore—altho I do air drop and wingsuit a lot in FC6 since the map is so huge… depends on my humor on the day.
FC6 is a fine game—but like many other fine games, that doesn't mean you'll like it—looking forward to your reaction
PS have you played any earlier FC game?