Is TESS replaceable by gound-based-small-telescope arrays? TESS is designed to perform an all-sky transiting exoplanet survey.


  TESS's survey will focus on nearby G, K and M type stars with apparent
  magnitudes brighter than magnitude 12. Approximately 500,000 stars will
  be studied, including the 1,000 closest red dwarfs.


Since its targets are very bright and its sensitivity is relatively worse than Kepler, I wonder whether it can be replaced by gound-based-small-telescope arrays. There can be no gaps in the time series too.
Depends on the wavelength ranges to be studied as well.  Quoting from the link you provided:


  The sole instrument on TESS is a package of four wide-field-of-view
  CCD cameras. Each camera features a low-noise, low-power 16.8
  megapixel CCD detector created by the MIT Lincoln Laboratory. Each has
  a 24° × 24° field of view, a 100 mm (4 in) effective pupil diameter, a
  lens assembly with seven optical elements, and a bandpass range of 600
  to 1000 nm


Atmospheric absorption has some serious peaks near 750 and 920 nm, which is one reason to place these cameras in orbit above the atmosphere.