Expanding grenade availability - a boon to 3/4 martials

[Subtext]

With the recent changes to rogues, the introduction of vigilante and the general fairly poor state of dex based characters, I would like to suggest the following:

Allow Shadowdancer and Assassin levels to scale with rogue levels when it comes to the DC, damage and unlocking grenades...not at the full rate but at 2:3.
The feat Simple Experimental Devices would still be required as before and it should not be available for either class.
Reason: This would constitute a boon primarily for dex based builds that are currently in a fairly bad spot without additionally favouring rogues that have recently undergone several improvements. It might also be considered as a placeholder in lieu of a bigger (and in case of SD certainly needed) rework of the affected classes.

Example: A Rogue(8), Fighter (4), Shadowdancer (16) takes Simple Experimental Devices. The effective level for using grenades would be 19 (8 from Rogue - 11 from 16 Shadowdancer levels (2x(16/3) rounded)).

Additionally, please consider to EITHER give Loremaster the equivalent to grenade scaling when they receive +x to caster level OR to give them a minor secret that allows them to synergize with Rogue/SD/etc levels.
Reason: Thematically the class is a nice fit for the more brainy rogues, especially when it comes to arcane trickster concepts. Mechanically however it doesn't mesh all that well.

[The GrumpyCat]

There's something to be said for class identity. These should remain a rogue, vigilantee and liberator tool. Giving them to assassins and Shadowdancers would errode that. Denyied.