You could definitely argue that Frieza was powerful enough to have contended with Goku and Vegeta in the Broly movie, but now? The Saiyans have risen above him by a huge level (especially if Goku unlocks MUI).
But I'm sure Frieza is still plotting to kill them, so what do you think his motives are now? How can he possibly carry out his plans with the Saiyans in the way?
Freeza was very much a threat in the Broly movie. Vegeta said as much at the beginning(he was legit worried about Freeza's power), and then Freeza proceeded to soak a beating from SS Broly for a full hour, without even powering down from his Golden form. That's WAY above what Goku/Vegeta were capable of at the time.
And while the Saiyans have definitely eclipsed Freeza at this point, I honestly wouldn't be at all surprised if Freeza was able to bridge that gap just by starting a serious training regimen again. His potential is stupid.
I don't even know what Freeza's endgame is anymore. During the ToP he implied that he wanted to usurp Zen-Oh and rule the multiverse, but short of inextricably obtaining the Super Dragon Balls, I don't see how that is remotely realistic.
Freeza only trained for 4 months and went from being weaker than he was during the Namek saga, to SSB Goku level... And all he did was routinely ragdoll Tagoma to receive that kind of upgrade.
And all Freeza could do while he was trapped in Hell is image training, and still came out equal to pre-ToP SSB Goku... And mind you, by that point Goku had:
-Trained for 3 days/years in the RoSaT.
-Received a zenkai from the U6vs.U7 Tourney.
-Received a few zenkais from the Zamasu arc.
...Yet Freeza was able to increase his power just as much, simply by *thinking* about fighting, lol.
Fast-forward to the Broly movie(post-ToP, so the Saiyans' powers had obviously increased exponentially), and Vegeta still feared Freeza's power/potential, and Freeza himself outperformed SSB Goku and SSB Vegeta against Broly.
So yeah, give Freeza a few months of real training(like Goku and Vegeta received), and I have no doubt that he could bridge the current gap.
The only Saiyan with greater potential/power growth than Freeza, is Broly.
If Jiren is still any indicator, then MUI's "unhittableness" can be overcome if the opponent has enough raw power. Jiren wasn't using UI, for example, yet was tagging Goku just fine because he powered up enough.
He could always strongarm Zuno, like Zamasu did.
Now actually gathering/moving the SDBs would likely be a problem for Freeza, given their size.
Broly's power-creep is untouchable. I've mentioned all this before, but...
-Base Broly starts off considerably weaker than base Vegeta.
-Base Broly becomes stronger than base Vegeta.
-Vegeta goes SS1 and is more powerful than base Broly.
-Base Broly becomes more powerful than SS1 Vegeta.
-Vegeta goes SSG and is more powerful than base Broly.
-Broly goes Ikari and is more powerful than SSG Vegeta.
-SSG Goku enters the fray and is swiftly overpowered by Ikari Broly.
-Goku goes SSB and is more powerful than Ikari Broly.
-Ikari Broly soon becomes ~ SSB Goku.
-Freeza kills Paragus which forces Broly to become SS.
-SS Broly is able to effortlessly wipe his ass with SSB Goku+SSB Vegeta as though they are weak feebs.
-Goku/Vegeta flee the battlefield, and they believe that fusion is the ONLY way to defeat Broly at this point.
-SS Broly beats the absolute shit out of Golden Freeza for a full hour, and Freeza fangirls over Broly's "astonishing" power the entire time. *Gogeta enters the fray*
-SS1 Gogeta and SS Broly engage in a battle that appears to be shattering dimensional barriers.
-Broly becomes FPSS, and his power increase was significant enough that Gogeta felt the need to powerup all the way from SS1 to SSB in response.
-SSB Gogeta has far greater skill than FPSS Broly, but none of the attacks he lands really do more than knock Broly down. In fact, the implication is that Broly just continued getting more powerful in lieu of the 'damage' he was taking.
-The only attack that would have put Broly down was SSB Gogeta's full power Kamehameha.
-At the end of it all, Goku states that Broly is probably > Beerus himself.
*And all of the above occurred over the course of like 2 hours. NO character in DB history has shown remotely close to that level of power growth in such a short amount of time. It's asinine.
King Vegeta called Broly a "mutant" at birth, so that's probably the best explanation we'll ever get for why he is so massively powerful compared to the other Saiyans.
Paragus said he could do oozaru stuff in his base form. Makes you wonder how the series would be different if vegeta and goku kept their tails and trained as monkeys
The fact that Broly was still able to gain the Oozaru amp without transforming out of his base form, without having a tail, and without the presence of a moon, is a huge testament to his "mutantness".
Freeza is a mutant from a mutant (King cold), whatever species King Cold is he's a mutant version of it and Freeza is a further aberrant.
Right now it looks like Freeza is putting the saiyans on the back burner and rebuilding his stranglehold on the universe + plotting to overthrow zeno
He's the only real interesting thing about Super, Toriyama should focus on his schemes more.
__________________ What CDTM believes;
Never let anyone else define you. Don't be a jerk just to be a jerk, but if you are expressing your true inner feelings and beliefs, or at least trying to express that inner child, and everyone gets pissed off about it, never NEVER apologize for it. Let them think what they want, let them define you in their narrow little minds while they suppress every last piece of them just to keep a friend that never liked them for themselves in the first place.
Never let anyone else define you. Don't be a jerk just to be a jerk, but if you are expressing your true inner feelings and beliefs, or at least trying to express that inner child, and everyone gets pissed off about it, never NEVER apologize for it. Let them think what they want, let them define you in their narrow little minds while they suppress every last piece of them just to keep a friend that never liked them for themselves in the first place.
I'd like to see an arc that buttons up the Freiza plotline once and for all. One final attack on Goku, Vegeta and Earth. Maybe he puts together a grand plan and puts it into motion after this Granola arc. Maybe they make Cooler canon and they team up.
edit, also I wonder if at this point the writers have forgotten Super is still supposed to be pre end of Z.