I have played piano since I was 5, but find I prefer a semi-weighted feel, because it allows me the flexibility to play in a traditional piano-like manner, as well as giving me the speed with which I can play leads and fast note sequences much faster. When I try to do that on a fully-weighted keyboard, it bogs down and limits how fast I can play something. Like real mushy when trying to play fast.
The other thing I found was that by and large, I get WAY better bang for the buck using sound modules (soft-synths) and a midi controller or simple home-piano/controller rather than on-board sounds.
A full synth is a compromise between features and cost, and many times it comes at the expense of sound quality.
For example, I have 24-bit sample-based piano instruments in Kontakt that are MASSIVE, where each note was sampled for a full 30 seconds at multiple velocities, where even the OVERTONES are present in as natural a form as possible (except for sympathetic vibration of other strings). One preset may be more than a GB in size.
A piano sample on a keyboard synth instead is made of artificially generated note length (looped), and often is only sampling maybe 1/3 of an octave and then generating the in between notes. They do this to save on the amount of storage and memory required for storing and playing that piano sound, and it just does not sound as good as my computer-based piano samples from Kontakt. A piano preset on a keyboard synth may only be a few MB in size, WAY lower in quality than my Kontakt piano sounds.
Additionally, the keyboard synth technology is a fixed technological 'snapshot' at the time of its creation, while soft synths can be fully reworked or swapped out for different ones, so the sonic capabilities of computer-based soft synths are literally endless, while a keyboard synth will always be limited to whatever sound producing level of technology it was designed with. You may spend 2-3 thousand for a good keyboard synth, and for that same money you could buy a top of the line controller (or a couple of them), AND several top of the line collections of top of the line sounds, like Komplete, or East West Strings, or other high-end sounds.
I have an Axiom Pro 61 controller for playing leads on, and for a 2nd controller I use a simple $250 Yamaha 76-note portable digital piano. That allowed me to purchase a $1000 microphone and Komplete 8 Ultimate, for less money than I would have spent on a traditional keyboard synth.
If you have your heart set on one of those traditional keyboard synths, then have a blast - I only offered all of the above comments to suggest you consider what you are really getting for all of that money, versus going the route of a controller and computer-based soft synths.
In any case, I hope you find great pleasure and endless inspiration with whatever route you end up choosing to go with. :)
Bob Bone