I think, that the objective of offering flowers is to reflect on three characteristics of existence, impermanence, stress and soullessness.
In addition, offering lotus flower has some different meanings.
In that basis may be, we can offer even some fruits or leaves too, if we needed.
However, like many Buddhist values, flowers offering have been deteriorated to comply with changes overtime.
My local temple altar got lot of artificial flowers. It is used more as a decoration.
I think the most important thing is to follow the Noble Eightfold Path.