I made a component in joomla 2.5 in mvc way which was not working in joomla 3, later found out it's because in joomla 3 previous mvc classes not working so is controller, view, model classes must be extended from Legacy classes like
JControllerLegacy, JViewLegacy ,JModelLegacy
and no other changes needed to make component compatible with joomla 3 as far as i knew.If there anything more to know then let me know for compatibility with j3. So instead of making two separate mvc components for joomla 2.5 and 3, i guess i can extend from these Legacy classes so that single component is enough for both joomla 2.5 and 3, right? and again what other things to be considered to produce successful MVC component which can be installed in both joomla versions.