An instrument is a set of easy-to-do vs. hard-to-do factors. The instruments and tools you use for composing and arranging - just like your personal skills as well - are bound to affect the actual content you produce, not only how quickly you get it done. If something is very hard to do with your tools, you may find yourself seeking to do something else instead, even if your music requires that hard-to-do element. And if something is very easy to do with your tools, you may find yourself doing that more than would be good for the end-result.
For some genres and types of music production, it's not important to have a keyboard at all, but for others it might be essential. Many hip-hop producers do everything with a 4x4 drum pad.
Do you want to play full-range piano? Then you need a full-range piano keyboard. But on the other hand, if you have a full-range piano, you may be tempted to play full-range piano, even if it is detrimental to your music. For a lot of types of pop music, it's better NOT to have a wide range, NOT to play too many notes simultaneously, and NOT to have velocity sensitivity for each note. Instead, have a very controlled number of elements, each with a very controlled range of pitches and dynamics. This might be perfectly doable on a 2-octave keyboard.
- Backing chords: 2 octaves are enough
- Lead melody: 2 octaves are enough
- Drum pattern: 2 octaves are enough
- Bass line: 2 octaves are enough
For sketching out a full chord progression with low bass and chords at the same time, 2 octaves is too narrow, 3-4 octaves are needed. But you don't have to do it that way, and there's a danger that you'll start making pianist-style things.
If you have too many keys, too many tracks, too many instruments, too many presets, too many plugins, too easily available, you might lose control and focus over what you're really trying to do.
Still, if you want to play a full-range piano part like a pianist, it's better to have a full-range piano keyboard. It's not the tools, it's what you do with them.
You could even look at your current situation as an opportunity. :) The Launchpad makes you think about the notes you play in a different way, doesn't it? Personally, I sometimes like to play new unfamiliar instruments where it's hard to produce notes, because then I'll have to think more about what notes to play and when. These notes are expensive, so I'll have to make every note count! If notes are cheap, you'll produce low-value music... right? ;)