The PC version actually had a ton of tweaks and settings that can cause VAST framerate variances with minimal visual impact. Tress FX never quite worked on my system , kind of flickered, had wonky physics and also took away close to 50% from my overall framerate.
Like many PC games, those above options I mention can be tweaked from low - medium - high - very high and in some cases - ultra. Just based upon my own experience with the game I'd anticipate 1 of 2 options , they max out everything and leave the tressFX out and on PS4 it's locked to 30 fps at 1080p / 30fps at 720p on xb1 OR they go for a higher framerate and have settings closer to high and manage 60 fps at 1080p on ps4 with rare slowdown and 30-60fps on xb1 at 900p. What would you lose in the special effects department ? well, level of detail settings would likely get tweaked, draw distance wouldn't be as far either way. Anti aliasing won't likely be turned up very high, just the lowest FXAA option on both consoles. DX11 features like SSAO /HBAO lighting might be left off (they are quite demanding), as well features such as tessellation (which effected the volume of vegetation on the forest floor most noticeably) might be left off.
There exists a 3rd option though, if the port has been worked on for a few months - perhaps the studio involved didn't just cram the PC version onto console ? Maybe they opted to rebuild and tweak it to push the target hardware ? wishful thinking I know but if they spent a bit more effort than dumping the PC version , they could possibly push the entire game at 1080p and perhaps even squeeze on a toned down tress FX AND end up with something that looks better then PC even if technically it's cheating somehow (using texture and polygon culling more efficiently maybe?). This method could result in the equivalent of 1080p 60fps with the appearance of maxed out visuals but I'm not holding my breath they would do it.
For those lamenting the fact it will probably be full price - well yeah, of course it will be. The target audience here is more likely those without PCs that haven't played it yet which is also why I don't think they'll do that 3rd method of porting - too expensive and square is hoping it just sell another 500K copies worldwide at just about a straight profit.
