The question was pretty open. Can *what* battery technology improve? Lead-Acid has been around for over a hundred years, and still in the past few years the spiral-core variant has been developed that is an obvious reliability improvement over regular wet cells.
Can alkalines be improved? Probably; Eveready, Duracell, and Energizer keep tinkering with their formulations to get longer life = more mAh per kg.
Can we find something better than alkalines to power flashlights? Yes of course - NiMH and LiIon for example. All of these are improvements over "garden variety" batteries, when judged by particular measures. But if you don't specify what measures you're interested in, and what technologies you're comparing against, the question is meaningless. And thus the vacuous answer.