I'm debating between this system or SRPG Studio and it  seems the deciding factor would be tile interactivity. 

I'm looking for tiles that have more specific effects for different classes or characters. To draw a familiar reference, in Fire Emblem: Sacred Stones (FE8)  the water tiles are traversable by flying types and berserkers. In SRPG Studios, this is actionable by having tiles have "traversability" that can be modified for different classes. So if a character has the "flying" class attached to their build, they can usually traverse any tile. So something to this effect is what I mean. 

I'm also interested in being able to modify your healing/damage tile effect to be class-specific.  To give the main example I have in mind, I'd like to create a "Fire Warrior" type who is not only able to traverse lava/flame tiles, but also heals from doing so. 

Thanks in advance for your time and help, and for having created such a helpful plug-in!

Currently terrain effects are not exactly the most complex thing about the TBS system. You can set traps and status effects and even set terrain to affect battlers based on their movement layer but things like class and such specifics are not included at this time.