I have worked with boards (other parties involved) that were a total PITA to remove from the panel. I dunno if this was because of the designer or the manufacturer. On my own designs I try to avoid really stupid shapes and just leave the tab routing and the panelization up to the manufacturer. After decades of experience, they have a pretty good feel for where and how many tabs are needed, as well as how best to manage their tooling changes for the material. In one case they took liberty of doing a really cool tab on an FPC that looks like it changed the outline a little*, but once torn out is smoother than regular tabs. The best part, you can rip the board out without any care, at all, never an exacto knife needed. This saves someone a lot of time. (I understand these particular FPC are actually laser cut, FWIW. I've seen some other manufacturers which look like they are routed.. and those tab are PITA on FPC).
*For first time in years, I just now looked at this under the microscope. What looks like two little nubs on the outline is actually just extra clearance in the copper layer, so they could cut a little arrow on either end of the tab to make sure it tears cleanly, with all the stress on the outer waste nub and not the board.