I find my first layer speed settings to be perfect under normal circumstances though (20mm/s on a UM2+), but for anything with multiple islands (e.g. M3/M4 post holes in a part, or fidget spinners with multiple closely spaced shells) the nozzle tends to drag the first (inner) outline away from the bed as it moves to do the outer shell line. I do typically use a z-hop of .2mm, which could be contributing to the problem in some cases, but bed adhesion isn't normally an issue as it's levelled to .1mm using a dial gauge.
The option to invert the shell line direction for the first layer only, and perhaps even a first layer z-hop toggle should help with bed adhesion in this situation, and prevent the need for a separate process to accomplish this.
Come to think of it, printing islands sequentially without optimisation might help me with the first layer in these cases, I will play around with separate processes but some of these would prove useful to have as first layer settings.