This assumes that planning is not an issue provided everything is below the tree line (rare exceptions allowed with dark green track). I also may have completely forgotten about the whole 'not over the top' thing
3 new large roads (two of them being from Stoke-on-Trent and Derby)
New railway / reopening of old railway to get there – public transport is shockingly bad, especially this year.
New car parks
Relocated Air car park
Improved or replaced monorail (Doppelmayr Cable Liner instead?)
Relocated rubbish centre
New hotel / accommodation (Enchanted Village) – already being done
More hotel entertainment / activities in the evenings
New Forbidden Valley entrance for hotel users only
Existing cable car frequency sorted (always seems to be a bit random how the gondolas are spaced out), and also sped up
New cable car from Adventure Land to Cloud Cuckoo Land (Doppelmayr)
New cable car from Mutiny Bay to Katanga Canyon (Doppelmayr)
Everything not mentioned receives an upgrade if required
Adventure Land
Extend Sonic Spinball with a new chain hill just before the first end, and go a bit further and faster, and smoother, with the non-inverted loop (Maurer Söhne)
New young children's roller coaster (Mack)
New Speed Buzz flat ride suitable for all ages (KMG)
X-Sector / Renamed
Retheming and renaming of section to more friendly and crazy theme (to suit the Smiler)
Demolition of Enterprise
Demolition of Submission – already done
Oblivion will keep the vertical drop, but everything else will be new (name, theme, station, etc.). Floorless (and hopefully flawless
) roller coaster, spreading around the entire section with multiple vertical drops and corkscrews, as well as going into the forest (B&M)
New Chaos style flat ride (the sort of crazy Enterprise that was built as a travelling fairground ride) in Enterprise’s place
New Experience flat ride in Submission's place (KMG)
Dark Forest
Rita extension (does another circle, with a 3rd train if possible) and partial retheming (dark green track? – Intamin)
New Superstar flat ride
Cloud Cuckoo Land
New children's caterpillar coaster, which sort of spreads over the whole area where people walk (Mack)
Area directly behind CCL
New section, with friendly, simple theming
New 4D rollercoaster built downwards, spreading around the entire section, interacting with other new roller coaster (S&S)
New general rollercoaster with corkscrews and inversions, interacting with other new roller coaster (B&M)
New King Loops flat ride (Fabbri?)
Forbidden Valley
Demolition of the Blade
Removal of Ripsaw (as much as I like Ripsaw in this very location it would have to be moved for a new rollercoaster)
Extension of Air from end with a new lift hill, to interact with a part of Nemesis and the new roller coaster, and retheming (B&M)
New super fast (no – really, super fast. Like, ridiculously.. neck-destroying fast.) launch roller coaster, setting off North West between Air, old Ripsaw, and the Skyride, going down to Katanga Canyon, interacting with the new roller coaster in the MB new section, and The Flume, before returning back up, interacting with Air once, then a secondary launch across the valley, interacting with Rita once, then back across to the start – a few inversions and banks but mainly up and down with very high speed (Intamin or Mack, more likely Intamin)
New Sicko flat ride in the Blade’s place (KMG)
New Tango flat ride next to Nemesis Sub-Terra (KMG)
Air car park / Aquazone
New section behind Air, with a water theme
Water Coaster (U shaped track) with a large variety of in lake and on track sections, waterfalls, etc., interweaving with other new rollercoaster
New general roller coaster (triangle track – Intamin) with many inversions, corkscrews, and 2x 80° drops, and a water spraying ring, interacting with other new rollercoaster
Replacement of entirely refurbished Ripsaw
New Top Scan flat ride
Maybe some other rides which I am yet to think of
Katanga Canyon
New Crazy Hoppers flat ride for most ages from young children
Mutiny Bay / MB New Section
Mutiny Bay split into two sections, with the new section having the Flume
MB New Section
New section have a fun and friendly but relaxed theme
Complete renovation and retheming of the Flume?
New inverted roller coaster (regular track – B&M) in new section, interacting with the Flume and new roller coaster from Forbidden Valley, and an 80° drop
New Extreme (the orbiter) flat ride in new section