The radar takes up the entire screen width? I always thought the radar was supposed to paint a compact yet quickly readable view of (1) the strategic environment and (2) objectives. It's much harder to scan across the entire top of the screen.
The gameplay functionality for Windhaven's radar is different from a typical flight sim. Ace Combat, Blazing Angels, X-Wing etc all have very noticeable HUD boxes around enemies. They have target lock mechanics that are central to gameplay and center on dogfights where you spin around a lot chasing a big arrow pointing at the enemy. The purpose of the radar is mostly to hint the player when it might be worthwhile to switch targets. In these games you have to switch to a map view to get a 'strategic picture', although that's mainly to check how you're doing clearing ground enemies, as fighter enemies keep spawning near you.
In Windhaven you are mostly facing monsters that are much slower, larger and less maneuverable than you. Weapon lethality is quite high so most of the difficulty comes from setting up decent gun passes, dodging return fire and maneuvering the birds themselves, which is a lot more challenging than aircraft controls due to the need for constant two-stick co-ordination. The tiny flock enemies late in the game are much more maneuverable than you, so no pointer chasing there either; you kill them with intelligent use of volume attacks and island defences. There is a very small amount of dogfighting (vs vulture cultists) but even there you are doing (low) energy maneuvering, not really pointer chasing. There are no HUD target boxes on any of the monsters, only enemy & ally birds get them (as otherwise they would be impossible to see at any sort of range). There are almost no ground targets (just a few special mission targets) so the strategic picture is mostly about which defenses are active, how they are configured, what groups of monsters are incoming and what their vectors are. I only use the 'big always-visible arrow to chase' mechanic for a few key mission objectives.
The purpose of the radar then is to hint the player where the monsters are when they can't see them, due to distance, fog, terrain or being at the wrong height level. It replaces the 'chase this arrow to find enemy' HUD element with something more informatie but slower to interpret. Which is absolutely fine, because the tactical picture does not change as rapidly as conventional sims and you won't need to look at the radar while executing hard maneuvers. As Hawkwings mentions, the radar is implemented as a 360 degree fisheye view, and the very wide aspect ratio is essential to that; it makes the box in the middle have the same 16:9 aspect ratio as the visible screen. This reinforces the fact that it is an extension of your normal vision for player intuitiveness. It also stylistically fits the game in that it represents a 'psychic sense' rather than a technological radar, and is functionally and visually distinct from technological flight sims.
even a fixed 2D square with a top down view looks more familiar than the system you're currently using, though maybe it's harder to tell with stills
Pressing A toggles between nothing, fish-eye 'radar' and top-down map. The map takes up most of the screen, shows the whole island with elevation lines, and is more opaque.
adding a tint/shading to it to better distinguish between it and the foreground. For a moment I though the spiky balls in the first picture were radar objects. I can easily see myself making that mistake in combat.
The original radar design was much more opaque than the second screenshot above; there was a bug when I took that which deleted the background pane. I was skeptical of the new reduced opacity of the radar and gauges when it was proposed, but it actually works fine. The reason is that these are static foreground elements against a moving background, and the brain is very good at distinguishing and filtering depth planes (even without focal cues). With this level of translucency the HUD elements are no longer distracting, but you can easily see them when you want to.