Your recollection is a bit fuzzy
Unreal did have updates that added things like Hardcore mode and a different server browser. (edit - thanks Gothik) And the Fusion map pack.
UT had four bonus packs, but I'd hardly call them small! The Inoxx pack had six maps, the DE bonus pack had 2 CTF maps and some mutators. Another had 11 maps, 3 characters, and Relics. The last had 12 maps and 2 characters.
Unreal Tournament 2003 bonus pack 1 had three new gametypes, 10 new maps, two new adrenaline combos, new announcer voices, and a music player. The UT2003 bonus pack 2 had 6 new maps from Digital Extremes.