[walrus1066]

It'd have to be a really heavy planet to see obvious gravitational lensing effects (I.e. Sun size).

We detect planets in other systems by seeing them pass in front of the host star, or we detect them radiating IR, or if exoplanet is really big, with small orbit, it's gravitational influence on the host star (I.e. see it 'wobble').

In all cases, exoplanet is quite close in orbit to star.

By contrast, if a big planet is orbiting sun, but really far away (>x100 earth-to-sun-distance), it'd be to cold to detect it radiating any IR, it'd be too far to see obvious effects of it's gravity.