Wrong as in “if I didn’t say that they would be trying to convince me on how good VLANs are instead of trying to convince you”. 
More seriously, I don’t think that it won’t work, only I believe keeping devices on one bridge really separated from the other might be complex to do.
In any case, trying setting it in that way would be a good thing as it will make you more familiar with the settings and commands, and you can always go back.
Just in case (shameless plug) these might be of use for a first time user:
http://forum.mikrotik.com/t/the-twelve-rules-of-mikrotik-club/182164/1
http://forum.mikrotik.com/t/gp-csa-for-mikrotik-devices/182176/1