@Amsanity
> but in practice I found out that 2.500 can already become challenging
Really? you missing a zero there right? 
I am using LDR and have all post processing turned off (no bloom sniff).
using ‘stat rhi’ / ‘stat fps’ tells me I am drawing 65K triangles / 150 draw calls comfortably on low end GPU chipsets (eg. Adreno 305/Mali T720) - this is will a reasonable amount of translucent materials.
My target is only 30fps, not 60fps and so must complete the frame in around 32milliseconds rather than 16milliseconds - I am seeing 16-25milliseconds depending on the device.
The biggest hit I found was resolution/fillrate (which is device specific).
Current low end GPU chips seem designed to work at 800x480 / 960x540, but manufactures sometime peer these chip with 1280x720 screen for marketing reasons.
1280x720 is almost double the pixels of 960x540 (do the math).
For devices with low end chipsets and high res screens you really need to set r.MobileContentScaleFactor 0.8 or 0.5 to make anything playable.
Unfortunately fixing this means writing a custom AndroidDeviceProfileSelectorModule to find these devices and push them to a low resolution.