One area that the Rams are ahead of many front offices in is contingency plans. In losing out on Miller, they didn't just try to go sign any old pass rusher off the street (many of which, who remain, wouldn't be a good fit at OLB as they're strictly 4-3 ends) but focused more on how do we make the whole team better and not just band aid a position.
Que bringing in Robinson and shopping Woods.
And now we have Wagner who is arguably a better upgrade to the entire defense than any mediocre and non-scheme fit OLB we could bring in. He still offers good coverage ability, strong tackling and BLITZ ability (imagine a LB who blitzes better than Troy Reeder and can also play LB!!!). Bringing him in may lead us to play more 2 LB schemes as opposed to 3 safety schemes as his ability in almost all areas is better than what bringing in one of our 3rd safeties can offer.
Is he as good a net positive as Miller? No. But he'll offer greater help to the defense overall than any other position besides corner (which they Rams will address) right now.
Rams will pivot, defense will pivot. I think it could work out great for 1-2 years.