I know of my country, Pakistan where ballots are serially numbered to guard against fraud.

Based on the question presented (and the 3 options given) then at face value I would be inclined to go with the second choice “No, not in the context of a highly trusted electoral process”; however, this must be elaborated on a little further.
 
In a stable democracy, with a highly-trusted electoral process and strict protection of civil rights, serialization of ballots (if desired) would be acceptable. However, if one is permitted to play devil’s advocate for a moment then the following question must be raised. If the electoral process (and the EMB) enjoy a high-level of trust then why would they still need to serialize ballots?

(Although I do not profess to be an expert on commercial printing processes), we must furthermore bear in mind that -- when using commercial printers -- introducing a serial number on the ballot itself also has implications in terms of the printing speeds and printing costs. The printing machines dealing with serialization typically run considerably slower than other commercial printing machines. Typically, commercial printers do not only charge in terms of consumables (i.e., paper, ink, screens, etc.) but also in terms of printing time. The longer your specific printing production run takes, the longer the equipment cannot be used to do other printing jobs and the more you will be charged.

In some cases, whether the ballot is serialized or not is irrelevant when it comes to perceptions related to the “secrecy of the vote” . In one particular election that I am aware of, voters were intimidated by being told that how they vote can be identified later on through their fingerprints as these would be left behind on the ballot paper when they touched it. (To avoid any unintended confusion, these were ordinary ballots where a voter places a mark on the ballot using a marking pen).

If the question posed was “Do you think a ballot with serial number is appropriate or beneficial?” I would be inclined to say no. Simply put: Serialization of ballots is indeed a poor substitute for appropriate due diligence within the electoral process!

I raised this question during our election observation mission in Togo, where polling officers were issuing ballot papers with serial numbers. Most probably out of ignorance, many were tearing the ballot paper off the bloc together with the serial number; as a result, most marked ballots in the boxes featured a traceable number on them.
I believe that, even if the system does not allow tracing the sequence by which voters casted their ballots and thus linking marked ballots with specific voters, in countries with high degrees of illiteracy and superstition, as well as little confidence in the transparency of the process, this can be a major source of voter intimidation and insecurity.

In Italy many years ago serial numbers on ballots were removed just to avoid fraud, in view of the risk of enabling the linkage of a specific ballot to a voter at polling station level.

It may not be wise to do opinion polls among the general public on a subject susceptible of being discussed in proper technical terms. You may consider for instance, the document “Review of Paper Ballot Design” by Dr. N Ben Fairweather, which is included among the ACE materials from where I quote: “If the use of serial numbers were to continue, or be replaced by alternative methods for tracing ballots, honesty requires that the electorate are educated that the ballot is not truly a secret ballot …”