One way to make the tank appear larger is to run it hotter. TO prevent danger of scalding, you would then install a tempering valve at the tank. This will give you more hot water. But, if you can't do this work yourself, the labor to add the tempering valve would be in the same order as changing the tank. An electric tank could last a very long time, or it could die tomorrow. Hopefully, when they installed it, they installed a drain pan for the inevitable time when it does start to leak.