"Holy Trinity" of Lenses - advice needed

Hi all, I switched from Nikon DX over to an OM-D about 2 months ago. I purchased the 12-50 kit lens as well as the Pana 25/1.4. The 25 doesn't leave my camera unless I want to take a wide angle/landscape shot, and I've been very unimpressed with the 12-50 can do (in my hands). With Nikon, my two favorite lenses to shoot with were the Sigma 10-20/3.5 and the Nikon 50/1.4. I recently purchased the Oly 12/2 to satisfy my wide angle hunger. Yes I know it's not as wide as I had before, but this is one awesome lens.

I'm now thinking about selling the 12-50 in order to offset the price of buying the Oly 45/1.8. Apart from losing out on weather sealing is there any reason to keep the kit lens if I have the 12/25/45 combo? Is there another zoom I should be looking into instead, maybe the 14-150? At some point in the future, I will have to look into the telephoto range of things, but for now 45 is as close as I'll need.

Thanks in advance for the advice.