There are a few ways to see if things are alright.
If you haven't decrypted then a crc check will tell you if a file got corrupted
If you have decryped then check the size of the Graphics Folder along with it's file & folder count.
If decrypted you should easily be able to look at the pictures
'Princess & Conquest v0.17.Bloom\Graphics\Titles1' contains the Main Menu
The size of your save files to see if any junk is stored in them. 2-6 MB looks like the average though if they are over 10 MB that might be a problem.
If you are using the debug script I use then your game folder should have a file called errors.txt, it contains graphics the game believes are missing. After fans stopped reporting them to Towerfag well they became a lower priority but still useful if you're hunting graphical errors.
3 seconds isn't great but given the optimization, or lack thereof, doesn't sound atrocious. Cleaning up the code would help improve things however the massive undertaking is a bit much for me
It took a considerable amount of time to clean up Game_Picture the last time I did it.
I seen The Last Sovereign have a transition glitch that temporarily makes the player run like speedy gonzales and that game has much cleaner code.
Some of it is Stacking Events, after a certain number it's not really efficient. Um take a war scene for example.
Lets say we have a 100 soldiers doing battle, if you have each soldier be 1 Event the engine has to process 100 Events per every few frames. Bogs the system down.
Now if you altered the scene to have 1 Event depicting 100 soldiers fighting it's significantly less resource intensive as only that event gets refreshed every few frames.
But what about the Camp Area?
Map 64
Contains 60 Events, each condition has to be checked when loading it so it's going to chug a bit.
This though doesn't seem to have added events since v0.17.11.
As for lines of code it went from 26446 to 27556 so 1110 new lines between Then and Now.
For High Potential Lag areas I would say the Camp, Tavern, and World Maps specifically World Map N as it being the original it's gotten more attention.
As for a culprit well Script Sapphire Action System IV might need some tlc as it handles Pathfinding. Tell me how far should a stone that's not meant to travel travel? I hypothesized this caused Save Bloat sometime ago but didn't have enough
guinea pigs I mean testers to throw me enough data to isolate it. Didn't help that I think the debugger I attached was cleaning the data for me. 300 MB Save just filled with 0s for the travel route. That has to be loaded into memory so yeah dependent on system that can take time.
Doesn't help that there is a glitch in the Patch System so it doesn't handle Map Update Patches all that well.