In System Shock 1, you pay attention to every note or email you get, just in case it contains critical information on what to do next.

System Shock 2 bringing in a radio buddy telling you what to do is ripping out one of the primary functions of such logs. This was a natural and organic way of handling the intersection of 'largely silent, undefined protagonist' and 'no direct interaction with friendly NPCs' and 'the objectives for the game are nonetheless more varied than just killing everything or getting to end-of-level locations'. Many of your objectives are fairly literally 'I found a note where a now-dead group of people trying to resist SHODAN's takeover were laying out their intended plan, so I guess I'll go execute that plan myself'. You were cut loose into the game world and left to fend for yourself, trying to figure out what's what from the clues scattered among emails and whatnot you find around the station. See, in System Shock 1, you didn't have a radio buddy constantly telling you exactly what to do next.

End of system shock 2