Here are some things I would love to see:
- Manual definition for the SI tables, either in ATSC or DVB;
- Transport Stream preview for audio synching, prior to creation (I don't know why, but the preview used today either takes way to long to start, doesn't play, or crashes for me - mainly using HD files);
I normally use another system to do it, using SMIL files instead of Transport Stream, and a hardware decoder - just to adjust audio synch.
- Presets for day to day use (because everytime I want to create a DVB TS, I have to manually set the PCR, padding, and final bitrate...);
- DVB Bitmap Subtitles insertion, using standard subtitle text files as input (Spruce STL, EBU STL, Senarist SON, Subrip SRT, Substation Alpha ***, etc.);
- Non-destructive trimming with TS streams (maintain the TS whole structure with SI tables and all TS parameters, but choose the input and output). By copying a TS file through FTP, and cutting connection prior to finish the transfer is a good example - the partial copy plays just fine and has all the parameters in it, although this procedure cannot produce frame accurate trimming

;
- Insertion of aditional ES streams to an existing TS file, with minor adustments to the final stream (final Bitrate and PID for the aditional stream) - the remux function doesn't allow you to enter an aditional file, and the mux function only accepts ES files;
- TS file merging (in the case when both files have similar parameters).