Google has kept its homepage clean with minimum possible buttons, but what still this homepage lacks from design point of view? Or what else could be added to it or removed to make it a better design?
Many good questions generate some degree of opinion based on expert experience, but answers to this question will tend to be almost entirely based on opinions, rather than facts, references, or specific expertise. If this question can be reworded to fit the rules in the help center, please edit the question.
The short answer is - nothing. Google has invested months and years of their time and money into researching their ux. Their home page contains exactly what their user needs.