Personally I wouldn't worry much about chirp (frequency pulling), unless it's really bad. It's not hard to copy, for a human anyway. It warms my heart whenever I work someone with a chirpy homebrew transmitter.
Key clicks, what you're calling splatter, is another matter entirely. You'll need some sort of circuit to shape your keying envelope or your key clicks will occupy an incredible bandwidth, possibly only limited to the bandwidth of your bandpass filter. 1 W is quite low power of course, but key clicks unfortunately are easily heard many kilohertz away (for egregious cases). And operators like to tune around to discover who has such an awful signal.
(Key clicks used to be a dirty Morse code contesting trick to keep one's frequency clear. No other station wants to be near in frequency to a loud clicky signal, because it's hard to copy when someone else's clicks are overlaid on the signal one is trying to copy. Certain well-known commercially-made transmitters were famous for making bad key clicks.)
Here's what a non-clicking signal looks like on an oscilloscope at audio frequencies (simulated, apparently).
