This isn't very good; it's actually really good if you place several ceramic chip bypass caps around the perimeter of that polygon, if you don't mind bottom side component placement.
Best scheme: lay out the circuit as a single placement and routing layer, as much as possible. Leave the other layer as solid ground, as much as possible.
Where traces need to cross, drop to the opposite layer for only a short length (this may entail more vias than a direct route, that's fine, vias are free).
Note that traces, vias, rows of component pads and so on, cause obstructions on one or both layers, so traces MUST be routed around them (or through, if connected). Wide pitch components sometimes allow routing through (mainly SOIC and DIP), but if the traces aren't connecting on the other row, you'll probably find it causes more congestion than it's worth.
QFNs are the most annoying, where you might not have any escape route from underneath the chip, so you have to drop vias there, or spend more space around it getting traces to the sides they need to be on. QFPs (no thermal pad) have some space there, but you should prefer ground there on one layer or the other. Or a well-bypassed supply, or both.
Finally, group traces together into buses of sorts, and fill in the negative space around them with ground pour. Stitch this with vias, at least at every peninsula. Don't bother to fill small islands; medium islands, connect with vias, just one is fine for smaller ones, use two or more for larger islands.
In this way, even where many traces have to be routed on the opposite layer, ground is never far away, whether above, below or beside. Note that anywhere two buses of traces cross, there is a complete hole in both top and bottom ground. Keep these holes small and infrequent.
In general, commit about half the layers to supply nets, in priority order. The remaining supplies are then routed as any other signal, with suitable considerations for trace width and bypassing.
For the two-layer case, some routing on the "plane" layer is inevitable, and that's why you want to keep opposite-layer routes small. That's also why you want to fill ground on both sides, so it averages out to, hopefully a bit more than one poured layer actually.
When you have four layers, for example, you can afford two for supplies and the rest for routing. GND takes priority, then whatever VCC supply/ies can be the other. Doesn't have to be a solid layer, likely you'll have different zones depending on what supply takes priority in a given area. (You can also fill the routing layers with ground or whatever, but it's harder to stitch -- you have to check four layers for via placement -- and doesn't have nearly as much benefit, as the inner layers do a surprisingly good job of shielding despite not being actually on top.)
Tim