Comment by dogma1138

It's not exactly known to be incomplete although everyone hopes it is, there are a few theoretical extensions to it like SUSY but currently all of them have failed to produce any tangible experimental results.

We thought that the LHC would quickly find physics beyond the standard model but alas it has found nothing which is a problem for many theories that want to replace or even substantially expand on it as many of their prediction were proven to be false.

At this point i would find it very unlikely that we will replace the standard model completely most likely scenario is that we will find an extension to it which will be proven correct and at this point it seems the model we have will not be extended as much as it was thought so previously.

It would require an extremely drastic discovery to essentially push the standard model out of it's current generalised state.

And the cosmological constant is not a gaping hole in any theory it's a problem for some its not a huge or (even a small) problem in the standard model if you want to find the biggest true problem with it currently you should look into neutrinos which are supposed to be massless according to the standard model but have a small non-zero mass in reality.

There are a few solutions to this problem both within the current model as well as extensions which range from a massless sterile neutrino to super symmetry and to a secondary mechanism through which particles may gain mass other than the Higgs field.