You’re definitely not the only one who feels that way. I’ve heard at least a couple other sticking points come up around authenticity/realism too: diagonal lines and textures for the fill tool come to mind.
I was just talking with @xymostech about this in The three traits of Shmeppy's design - #4 by johncs. A big bet I’m making with Shmeppy is hoping there’s a market for a not-designed-for-power-users VTT. What really sucks about that is that some folks like you who are really excited about Shmeppy might ultimately not be well-served by it 
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Though I hope that even folks like you who really like spending a lot of time pre-drawing maps and doing lots of prep work, will still find it hella convenient to have a tool on-hand that doesn’t require that.
I also hope down the line I can find a way to blend the two worlds of power-user and non-power-user in such a way that, as you say, “doesn’t disrupt the quick and easy play uses.” I think allowing the uploading of pre-made map images (ex: those made in campaign cartographer) will actually go a long way towards that 
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These are all pretty high-level thoughts though. For each specific feature like this one, it’s gonna be a new decision. A new question of balancing “‘staying authentic’ for more users vs the brutal simplicity design”, as you say.