This is a fascinating question because it really is a bit of a yes and a no. Ricimer was a powerful and competent general who won many victories for the Empire, yet he was a key part of the fifth century phenomenon of weak puppet emperors. I wish I had a good biogaphy of Ricimer in front of me, something like The Original Godfather: Ricimer and the Fall of Rome by Max Flomen, or Generalissimos of the Western Roman Empire by John O'Flynn, but I don't, so I won't be able to get into the nitty-gritty for you right now, but I can give you a broad idea of the answer.

Ricimer as a general (a magister militum) is comparable to other figures like Augustus or Aurelian, who came to power when Rome was in a major period of crisis. Crises naturally had many effects on what kind of person could rise to power and what the focus of their regime would be. Weaker and more eccentric emperors, like Nero or Elagabalus, could only survive in more peaceful times. Periods of crisis necessitated turning to stronger men to lead. Ricimer was the perfect choice in this regard. He had a proven military track record under earlier magistri such as Aetius, and his experience served him well, winning many more victories while holding de facto power. This helped secure the Empire in the short-term. If someone less experienced and less competent had been in Ricimer's place and had lost those battles, the western Empire may have collapsed sooner. It is not a coincidence that only four years after Ricimer's death Odoacer conquered Rome the deposed the emperor, ending the Empire in the west.

Yet Ricimer was a very important part of a trend that severely weakened the Empire. This trend was the result of changes to the Roman military which bled over into Roman politics. During the fourth century, the Roman army had come to rely heavily upon soldiers supplied through agreements with barbarian groups. These soldiers were known as foederati. Importantly, they were commanded by their own leaders, rather than by Romans, which elevated the power and influence of these barbarian leaders. Many of them became the most powerful generals in the Empire. However, the Roman senate and people would never accept a non-Roman as an emperor. So these powerful generals, if they had the ambition and drive to gain more power (which they all did) had the choice to turn against the Empire and conquer its land for themselves, or appoint a puppet emperor which they could control. Both choices weakened the Empire over time, and Ricimer was a part of this system.

Thus it is hard to say whether Ricimer was good or bad for the Empire, because he did not really have an effect on its ultimate survival or collapse. Ricimer staved off the collapse for some time, but he was a part of the system that eventually brought it down. Without him, the result would have been the same.