Yep, too many apps will slow down the boot. I don't think it matters if they're on the SD or not though since most of the slowdown is from the apps loading into the background during boot.
I discovered that the LG Esteem internal memory "space" gets fragged after too many app/pic installs/removes or any data... just over time period.
FORMATTING THE INTERNAL SD (I pulled my 32GB card out just to be safe) WILL IMPROVE BOOT TIME....
Even better Idea (what I do)...
1 I deleted the 20GBs of music from my 32GB SD (I'm on $70 plan so rhapsody is awesome, I just stream 4g all the time) It Caused my media scan time to be over 10 min.
2I pulled ONLY the files I NEEDED from card pics/roms/ect,
3 Formatted the 32GB SD (using the Esteem not my CPU. I formatted card on PC one time, It was ridiculously slow.)
4 put my pics/roms back on SD.
5 I used CWM to Format internal SD, system/data/fatory reset, cleared cache/davilik, then installed GSEII ROM and plague Kernal.
Once I got my wallpaper/settings tuned (but no apps) I performed A CWM backup.
A restore point On a fresh rom install with formatted internal/external SD's IS AWESOME
System slows down? restore it to fresh. The entire Disk image is new, so it's not fragmented. it BOOT's FASTER.
Just resintall any apps you need (I added all my apps into the ROM.zip, So I don't waste time with titanium backup anymore)
it's what I've Done the last 20 years on PC's fresh windows install, on formatted drive.
I do it every few months on my laptop, and about once a month on my Esteem.
One Great thing with "Rom Manager" you can click the restore point, go smoke one, come back and the phone is at the lock screen fully restored. Unlike manually flashing in CWM then rebooting yourself. the Rom Manager is Automatic. goes into CWM restores and reboots itself. I LOVE IT.
TAKE MY ADVICE, AT LEAST FORMAT INTERNAL SD every once a while if you dont want to restore.