Has The Women's Division Suffered Since Rousey Left??

Yes, but as others have said its more due to dumpster fire booking mixed with Wrestlemania main event hangover than her absence. The Women's division was white hot around last year's Survivor Series, but has been steadily declining since then, and nosediving since Wrestlemania. Here are a few examples:

The Riott Squad were really starting to pick up steam, particularly in the feud with Bayley and Sasha. That went nowhere and they became jobbers - culminating in a Cena/Wyatt Family level of burial to Rhonda; Ruby was so lucky she got it twice. Now they're split, Ruby is hurt, Liv and Sarah have shown up once, and then disappeared.

Asuka (this pissed me off to no end) was picking up steam as SDL champ. She's booked to lose that belt in a throwaway match to Charlotte in an unnecessary addition to the overbooked mess that was the Wrestlemania main event (more on that in a second).

The women's tag titles, highly touted as revolutionary were not won by a team that could really use the accolade to get over (the aforementioned Riott Squad, Sonya and Mandy, or the IIconics (more on them next)...but to Bayley and Botcha, who definitely didn't need it. (This is not helped by rumors that the belts were basically given to them to shut them the hell up and there was no other plan. I don't know if this is true, but the rumor doesn't help).

Becky Lynch, a genuine success story, she wasn't even meant for her position, but she won EVERYONE over, myself included. She gets an opportunity at Survivor Series to be in a match that EVERYONE wants to see...then Nia Jax ruins it for everyone. What happens? Charlotte gets the shot, in a match that defied logic and was seemingly designed to make Charlotte the new Becky. It almost worked, but what they didn't account for is the power of a grassroots success story. Everyone wanted Rhonda vs Becky even more than before. That was your Wrestlemania main event, and it would've been awesome. HOWEVER...I envision Vince McMahon walking into the meeting and saying 'no no no, this is far too good. We need to make this horrible, dammit!'. Charlotte is thrown in because she 'deserves it' even though people wanted the one on one match, proceeded to put Becky through a comedically bad series of trials (including a fake injury and culminating in one of the worst segments in television history) on the way to the main event, while still loudly and proudly touting this historic, groundbreaking, momentous occasion). After it was done I was sick to death of Becky (who I was previously a fan of), Charlotte (who I already wasn't a fan of), and Rhonda and never wanted to see another female main event again.

Since then, the women's tag belts mean nothing and they did a better job of derailing the IIconics than making them. Becky has lost ALL of her shine from the Man. Asuka is still languishing in the shuffle, and the one new star that they almost made, Lacey Evans, has dropped off of the face of the earth. Charlotte is facing a returning legend as Summerslam (not that she needs the accolade), Bayley is facing Ember (a bright spot if your forget that she was pinned by the champ cleanly a few weeks back) and Becky is facing....Natalya...again.

Its definitely not just the women's division, the booking is awful across the board, but between how nauseatingly touted the women's division has been, particularly since Wrestlemania, its much more damaging.

This is the Raw Womens Championship match at Summerslam. Thatll put butts in seats.

Yep. Big time. Ronda is a huge star and was great in the ring, she's sorely missed.

That’s true! They only have 9 active women on Raw (excluding injured wrestlers and Sasha). There are 13 on Smackdown (including Lana and Zelina who are off and on). It’s possible to make every one of them relevant with three women’s titles being passed around. Especially since one of the titles is a tag belt.

I honestly don’t see why they created a women’s tag belt if it was just gonna sit around like this. Hopefully the Alexa and Nikki win will rejuvenate it but I doubt.

It doesn't help when most of the roster can't wrestle for crap. The Iiconics are terrible in the ring and Natayla is a bore to watch.

To add, it also doesn't help that the fans/audience during the women's matches at best just sit there or worse start chanting "this is boring".
Even if the WWE decides to get their act together with the Women's division, they are going to have to find a way to get people to actually care and get involved.
The problem there is that is what Rousey brought to the table. It made the Women's division look like it was at the same level as the men. Not just the WNBA of the WWE.

But at the same time, the pressure and heat for the WWE to be inclusive, pro-women, etc., has died down. So they get put on the back burner with the hope that Becky, Charlotte, and returning legends can help coast along.

Rousey brought star power to this division and without her more or less ratings have gone down

The women's division suffers any time that giant child Bayley has her hands on the title. Her gimmick is so overplayed and just boring. Her matches are snoozfests and I haven't cared for anything she's done since winning the title. It's not just the lack of Rousey, it's the current state of affairs with the entire division on all brands (Raw, Smackdown, and NXT). Even lynch has gotten bland after they have over saturated the screen with her and Rollins real life relationship.

Last night was the 1st time I've found myself hoping for someone, whether it be Nia or Sasha, to come out and at least Have some sort of swerve. And trust me, I never thought I would be asking to see either of those 2