Then I replaced it with a 5" chartplotter. I'm afraid that this was a huge improvement.
I had the same experience.
On my Catalina 25 I used a Garmin Oregon as my chart plotter using the free charts available for the Seattle area. The display is about 2.5" and it was mounted on the companionway bulkhead.
The display was small enough that I often reverted to using an iPad running Navionics to navigate with and left the Garmin handheld just showing me numbers (speed, current time, etc).
On my newer Pearson I have a helm mounted plotter with a 7" screen. It also has a number of transducers: speed, depth, wind. The 7" screen is a great size that makes navigation on the plotter a lot easier.
I still have paper charts and also carry a Nexus 7 tablet with Navionics running on it. The Nexus 7 is a great backup, it has a built in GPS chip and the 7" screen is mostly usable in bright sun. It's not as good as the real chart plotter though, and battery life is terrible when running Navionics. It does double duty as a remote (in cabin) display for the plotter when I'm anchored.
The price difference between a basic 5" plotter with depth and a handheld with charts isn't that great these days, so I'd just get the 5" plotter at a minimum.