Why not have similar option and parameter structures for idgrey, idnlgrey, idpoly,...

Many things have improved in the System Identification Toolbox from 2009b to 2012b. However, as I'm porting my old scripts, I'm still missing a more unified approach to the properties and identification options of the models. In the end it's "just" a sequence of data, models(time, parameters), optimization routines...

Example: In 2009b I created a list of option key value pairs to use with the pem command, which I applied to idgrey and idnlgrey model objects. In 2012b I have to create an options object with greyestOptions for idgrey estimation, but still use my old-fashioned list for idnlgrey estimation.

Similarly, why not have the same parameter structure for idgrey and idnlgrey. One has the parameter option 'free', the other 'fixed'.

In my opinion it's about time to tackle this. What do you think? How do you handle different model classes?