I don't know the Baron, I did my multi-engine training on a P2006T, which is a pure trainer. I really don't see the benefits in using an expensive Baron especially considering the more complicated systems. The aim of multi-engine rating program consists of 6 hours and the aim is to familiarise the trainer with asymmetric thrust flying. Something similar with the Multi-Engine IR program: the aim is to fly the procedures correctly in normal and OEI conditions. The handling of such systems just increase the workload with no benefit that can be taken from it during initial multi-engine and IR training.
Another reason why the Baron is not used in Europe is that of Eurocontrol navigation fees. The Baron has a MTOW exceeding 2 tonnes and it burns expensive Avgas fuel. Definitely a no go for most schools.
This is why the DA42 and P2006T are succeeding in the training industry: they're light and they burn cheap Jet-A1 or Mogas. Piper is also working on a diesel version of the Seminole.